Auto merge of #13596 - nox:inline, r=Ms2ger

Get rid of dom::bindings::global

Globals in that PR are now represented by the fake IDL interface `GlobalScope`.

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---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13596)
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170 files changed, 1595 insertions, 1742 deletions

diff --git a/components/net_traits/request.rs b/components/net_traits/request.rs
index 2a84c91c759..4380baf3a09 100644
--- a/components/net_traits/request.rs
+++ b/components/net_traits/request.rs
@@ -174,8 +174,6 @@ pub struct Request {
     pub body: RefCell<Option<Vec<u8>>>,
     // TODO: client object
     pub is_service_worker_global_scope: bool,
-    // pub client: GlobalRef, // XXXManishearth copy over only the relevant fields of the global scope,
-                              // not the entire scope to avoid the libscript dependency
     pub window: Cell<Window>,
     // TODO: target browsing context
     pub keep_alive: Cell<bool>,
diff --git a/components/script/body.rs b/components/script/body.rs
index 276d6425d2f..c5b6008c363 100644
--- a/components/script/body.rs
+++ b/components/script/body.rs
@@ -4,12 +4,12 @@
 
 use dom::bindings::codegen::Bindings::FormDataBinding::FormDataMethods;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::USVString;
 use dom::blob::{Blob, BlobImpl};
 use dom::formdata::FormData;
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use encoding::all::UTF_8;
 use encoding::types::{DecoderTrap, Encoding};
@@ -42,11 +42,11 @@ pub enum FetchedData {
 // https://fetch.spec.whatwg.org/#concept-body-consume-body
 #[allow(unrooted_must_root)]
 pub fn consume_body<T: BodyOperations + Reflectable>(object: &T, body_type: BodyType) -> Rc<Promise> {
-    let promise = Promise::new(object.global().r());
+    let promise = Promise::new(&object.global());
 
     // Step 1
     if object.get_body_used() || object.is_locked() {
-        promise.reject_error(promise.global().r().get_cx(), Error::Type(
+        promise.reject_error(promise.global().get_cx(), Error::Type(
             "The response's stream is disturbed or locked".to_string()));
         return promise;
     }
@@ -77,7 +77,7 @@ pub fn consume_body_with_promise<T: BodyOperations + Reflectable>(object: &T,
                                                       body_type,
                                                       object.get_mime_type());
 
-    let cx = promise.global().r().get_cx();
+    let cx = promise.global().get_cx();
     match pkg_data_results {
         Ok(results) => {
             match results {
@@ -98,13 +98,14 @@ fn run_package_data_algorithm<T: BodyOperations + Reflectable>(object: &T,
                                                                body_type: BodyType,
                                                                mime_type: Ref<Vec<u8>>)
                                                                -> Fallible<FetchedData> {
-    let cx = object.global().r().get_cx();
+    let global = object.global();
+    let cx = global.get_cx();
     let mime = &*mime_type;
     match body_type {
         BodyType::Text => run_text_data_algorithm(bytes),
         BodyType::Json => run_json_data_algorithm(cx, bytes),
-        BodyType::Blob => run_blob_data_algorithm(object.global().r(), bytes, mime),
-        BodyType::FormData => run_form_data_algorithm(object.global().r(), bytes, mime),
+        BodyType::Blob => run_blob_data_algorithm(&global, bytes, mime),
+        BodyType::FormData => run_form_data_algorithm(&global, bytes, mime),
     }
 }
 
@@ -132,7 +133,7 @@ fn run_json_data_algorithm(cx: *mut JSContext,
     }
 }
 
-fn run_blob_data_algorithm(root: GlobalRef,
+fn run_blob_data_algorithm(root: &GlobalScope,
                            bytes: Vec<u8>,
                            mime: &[u8]) -> Fallible<FetchedData> {
     let mime_string = if let Ok(s) = String::from_utf8(mime.to_vec()) {
@@ -144,7 +145,7 @@ fn run_blob_data_algorithm(root: GlobalRef,
     Ok(FetchedData::BlobData(blob))
 }
 
-fn run_form_data_algorithm(root: GlobalRef, bytes: Vec<u8>, mime: &[u8]) -> Fallible<FetchedData> {
+fn run_form_data_algorithm(root: &GlobalScope, bytes: Vec<u8>, mime: &[u8]) -> Fallible<FetchedData> {
     let mime_str = if let Ok(s) = str::from_utf8(mime) {
         s
     } else {
diff --git a/components/script/devtools.rs b/components/script/devtools.rs
index d515d1fb99a..dcaee91c843 100644
--- a/components/script/devtools.rs
+++ b/components/script/devtools.rs
@@ -13,13 +13,13 @@ use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::LocationBinding::LocationMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::conversions::{ConversionResult, FromJSValConvertible, jsstring_to_str};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::DOMString;
 use dom::browsingcontext::BrowsingContext;
 use dom::element::Element;
+use dom::globalscope::GlobalScope;
 use dom::node::Node;
 use dom::window::Window;
 use ipc_channel::ipc::IpcSender;
@@ -33,7 +33,7 @@ use uuid::Uuid;
 
 
 #[allow(unsafe_code)]
-pub fn handle_evaluate_js(global: &GlobalRef, eval: String, reply: IpcSender<EvaluateJSReply>) {
+pub fn handle_evaluate_js(global: &GlobalScope, eval: String, reply: IpcSender<EvaluateJSReply>) {
     // global.get_cx() returns a valid `JSContext` pointer, so this is safe.
     let result = unsafe {
         let cx = global.get_cx();
@@ -245,7 +245,7 @@ pub fn handle_modify_attribute(context: &BrowsingContext,
     }
 }
 
-pub fn handle_wants_live_notifications(global: &GlobalRef, send_notifications: bool) {
+pub fn handle_wants_live_notifications(global: &GlobalScope, send_notifications: bool) {
     global.set_devtools_wants_updates(send_notifications);
 }
 
@@ -271,7 +271,8 @@ pub fn handle_request_animation_frame(context: &BrowsingContext,
     };
 
     let doc = context.active_document();
-    let devtools_sender = context.active_window().devtools_chan().unwrap();
+    let devtools_sender =
+        context.active_window().upcast::<GlobalScope>().devtools_chan().unwrap().clone();
     doc.request_animation_frame(box move |time| {
         let msg = ScriptToDevtoolsControlMsg::FramerateTick(actor_name, time);
         devtools_sender.send(msg).unwrap();
diff --git a/components/script/dom/attr.rs b/components/script/dom/attr.rs
index d5a00e6c1fa..f322204fc4b 100644
--- a/components/script/dom/attr.rs
+++ b/components/script/dom/attr.rs
@@ -5,7 +5,6 @@
 use devtools_traits::AttrInfo;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::AttrBinding::{self, AttrMethods};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap};
 use dom::bindings::js::{LayoutJS, Root, RootedReference};
@@ -66,7 +65,7 @@ impl Attr {
                                                    namespace,
                                                    prefix,
                                                    owner),
-                           GlobalRef::Window(window),
+                           window,
                            AttrBinding::Wrap)
     }
 
diff --git a/components/script/dom/beforeunloadevent.rs b/components/script/dom/beforeunloadevent.rs
index b66df9429dc..413a26a8de8 100644
--- a/components/script/dom/beforeunloadevent.rs
+++ b/components/script/dom/beforeunloadevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::BeforeUnloadEventBinding;
 use dom::bindings::codegen::Bindings::BeforeUnloadEventBinding::BeforeUnloadEventMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use string_cache::Atom;
 
 // https://html.spec.whatwg.org/multipage/#beforeunloadevent
@@ -29,13 +29,13 @@ impl BeforeUnloadEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<BeforeUnloadEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<BeforeUnloadEvent> {
         reflect_dom_object(box BeforeUnloadEvent::new_inherited(),
                            global,
                            BeforeUnloadEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable) -> Root<BeforeUnloadEvent> {
diff --git a/components/script/dom/bindings/callback.rs b/components/script/dom/bindings/callback.rs
index 7e6bb3534fb..709dab31049 100644
--- a/components/script/dom/bindings/callback.rs
+++ b/components/script/dom/bindings/callback.rs
@@ -5,8 +5,8 @@
 //! Base classes to work with IDL callbacks.
 
 use dom::bindings::error::{Error, Fallible, report_pending_exception};
-use dom::bindings::global::global_root_from_object;
 use dom::bindings::reflector::Reflectable;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{Heap, MutableHandleObject, RootedObject};
 use js::jsapi::{IsCallable, JSContext, JSObject, JS_WrapObject};
 use js::jsapi::{JSCompartment, JS_EnterCompartment, JS_LeaveCompartment};
@@ -165,8 +165,8 @@ impl<'a> CallSetup<'a> {
                                      callback: &T,
                                      handling: ExceptionHandling)
                                      -> CallSetup<'a> {
-        let global = unsafe { global_root_from_object(callback.callback()) };
-        let cx = global.r().get_cx();
+        let global = unsafe { GlobalScope::from_object(callback.callback()) };
+        let cx = global.get_cx();
 
         exception_compartment.ptr = unsafe {
             GetGlobalForObjectCrossCompartment(callback.callback())
diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 4ea45ef9ded..24826ced714 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -817,16 +817,16 @@ def getJSToNativeConversionInfo(type, descriptorProvider, failureCode=None,
                 { // Scope for our JSAutoCompartment.
 
                   rooted!(in(cx) let globalObj = CurrentGlobalOrNull(cx));
-                  let promiseGlobal = global_root_from_object_maybe_wrapped(globalObj.handle().get());
+                  let promiseGlobal = GlobalScope::from_object_maybe_wrapped(globalObj.handle().get());
 
                   rooted!(in(cx) let mut valueToResolve = $${val}.get());
                   if !JS_WrapValue(cx, valueToResolve.handle_mut()) {
                     $*{exceptionCode}
                   }
-                  match Promise::Resolve(promiseGlobal.r(), cx, valueToResolve.handle()) {
+                  match Promise::Resolve(&promiseGlobal, cx, valueToResolve.handle()) {
                       Ok(value) => value,
                       Err(error) => {
-                        throw_dom_exception(cx, promiseGlobal.r(), error);
+                        throw_dom_exception(cx, &promiseGlobal, error);
                         $*{exceptionCode}
                       }
                   }
@@ -1927,10 +1927,12 @@ class CGImports(CGWrapper):
             if t in dictionaries or t in enums:
                 continue
             if t.isInterface() or t.isNamespace():
-                descriptor = descriptorProvider.getDescriptor(getIdentifier(t).name)
-                extras += [descriptor.path]
-                if descriptor.interface.parent:
-                    parentName = getIdentifier(descriptor.interface.parent).name
+                name = getIdentifier(t).name
+                descriptor = descriptorProvider.getDescriptor(name)
+                if name != 'GlobalScope':
+                    extras += [descriptor.path]
+                parentName = descriptor.getParentName()
+                if parentName:
                     descriptor = descriptorProvider.getDescriptor(parentName)
                     extras += [descriptor.path, descriptor.bindingPath]
             elif t.isType() and t.isMozMap():
@@ -2523,7 +2525,8 @@ class CGWrapMethod(CGAbstractMethod):
     def __init__(self, descriptor):
         assert not descriptor.interface.isCallback()
         assert not descriptor.isGlobal()
-        args = [Argument('*mut JSContext', 'cx'), Argument('GlobalRef', 'scope'),
+        args = [Argument('*mut JSContext', 'cx'),
+                Argument('&GlobalScope', 'scope'),
                 Argument("Box<%s>" % descriptor.concreteType, 'object')]
         retval = 'Root<%s>' % descriptor.concreteType
         CGAbstractMethod.__init__(self, descriptor, 'Wrap', retval, args,
@@ -2754,7 +2757,7 @@ assert!((*cache)[PrototypeList::Constructor::%(id)s as usize].is_null());
                 getPrototypeProto = "prototype_proto.set(JS_GetObjectPrototype(cx, global))"
         else:
             getPrototypeProto = ("%s::GetProtoObject(cx, global, prototype_proto.handle_mut())" %
-                                 toBindingNamespace(self.descriptor.prototypeChain[-2]))
+                                 toBindingNamespace(self.descriptor.getParentName()))
 
         code = [CGGeneric("""\
 rooted!(in(cx) let mut prototype_proto = ptr::null_mut());
@@ -2808,8 +2811,9 @@ assert!((*cache)[PrototypeList::ID::%(id)s as usize].is_null());
                 properties["length"] = methodLength(self.descriptor.interface.ctor())
             else:
                 properties["length"] = 0
-            if self.descriptor.interface.parent:
-                parentName = toBindingNamespace(self.descriptor.getParentName())
+            parentName = self.descriptor.getParentName()
+            if parentName:
+                parentName = toBindingNamespace(parentName)
                 code.append(CGGeneric("""
 rooted!(in(cx) let mut interface_proto = ptr::null_mut());
 %s::GetConstructorObject(cx, global, interface_proto.handle_mut());""" % parentName))
@@ -3164,16 +3168,15 @@ class CGCallGenerator(CGThing):
 
         if isFallible:
             if static:
-                glob = ""
+                glob = "&global"
             else:
-                glob = "        let global = global_root_from_reflector(this);\n"
+                glob = "&this.global()"
 
             self.cgRoot.append(CGGeneric(
                 "let result = match result {\n"
                 "    Ok(result) => result,\n"
                 "    Err(e) => {\n"
-                "%s"
-                "        throw_dom_exception(cx, global.r(), e);\n"
+                "        throw_dom_exception(cx, %s, e);\n"
                 "        return%s;\n"
                 "    },\n"
                 "};" % (glob, errorResult)))
@@ -3383,7 +3386,7 @@ class CGAbstractStaticBindingMethod(CGAbstractMethod):
 
     def definition_body(self):
         preamble = CGGeneric("""\
-let global = global_root_from_object(JS_CALLEE(cx, vp).to_object());
+let global = GlobalScope::from_object(JS_CALLEE(cx, vp).to_object());
 """)
         return CGList([preamble, self.generate_code()])
 
@@ -3435,7 +3438,7 @@ class CGStaticMethod(CGAbstractStaticBindingMethod):
         nativeName = CGSpecializedMethod.makeNativeName(self.descriptor,
                                                         self.method)
         setupArgs = CGGeneric("let args = CallArgs::from_vp(vp, argc);\n")
-        call = CGMethodCall(["global.r()"], nativeName, True, self.descriptor, self.method)
+        call = CGMethodCall(["&global"], nativeName, True, self.descriptor, self.method)
         return CGList([setupArgs, call])
 
 
@@ -3489,7 +3492,7 @@ class CGStaticGetter(CGAbstractStaticBindingMethod):
         nativeName = CGSpecializedGetter.makeNativeName(self.descriptor,
                                                         self.attr)
         setupArgs = CGGeneric("let args = CallArgs::from_vp(vp, argc);\n")
-        call = CGGetterCall(["global.r()"], self.attr.type, nativeName, self.descriptor,
+        call = CGGetterCall(["&global"], self.attr.type, nativeName, self.descriptor,
                             self.attr)
         return CGList([setupArgs, call])
 
@@ -3542,7 +3545,7 @@ class CGStaticSetter(CGAbstractStaticBindingMethod):
             "    throw_type_error(cx, \"Not enough arguments to %s setter.\");\n"
             "    return false;\n"
             "}" % self.attr.identifier.name)
-        call = CGSetterCall(["global.r()"], self.attr.type, nativeName, self.descriptor,
+        call = CGSetterCall(["&global"], self.attr.type, nativeName, self.descriptor,
                             self.attr)
         return CGList([checkForArg, call])
 
@@ -5249,12 +5252,12 @@ class CGClassConstructHook(CGAbstractExternMethod):
 
     def definition_body(self):
         preamble = CGGeneric("""\
-let global = global_root_from_object(JS_CALLEE(cx, vp).to_object());
+let global = GlobalScope::from_object(JS_CALLEE(cx, vp).to_object());
 let args = CallArgs::from_vp(vp, argc);
 """)
         name = self.constructor.identifier.name
         nativeName = MakeNativeName(self.descriptor.binaryNameFor(name))
-        callGenerator = CGMethodCall(["global.r()"], nativeName, True,
+        callGenerator = CGMethodCall(["&global"], nativeName, True,
                                      self.descriptor, self.constructor)
         return CGList([preamble, callGenerator])
 
@@ -5496,10 +5499,6 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'dom::bindings::codegen::InterfaceObjectMap',
         'dom::bindings::constant::ConstantSpec',
         'dom::bindings::constant::ConstantVal',
-        'dom::bindings::global::GlobalRef',
-        'dom::bindings::global::global_root_from_object',
-        'dom::bindings::global::global_root_from_object_maybe_wrapped',
-        'dom::bindings::global::global_root_from_reflector',
         'dom::bindings::interface::ConstructorClassHook',
         'dom::bindings::interface::InterfaceConstructorBehavior',
         'dom::bindings::interface::NonCallbackInterfaceObjectClass',
@@ -5593,6 +5592,7 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'dom::bindings::weakref::WeakBox',
         'dom::bindings::weakref::WeakReferenceable',
         'dom::browsingcontext::BrowsingContext',
+        'dom::globalscope::GlobalScope',
         'mem::heap_size_of_raw_self_and_children',
         'libc',
         'util::prefs::PREFS',
@@ -5744,33 +5744,38 @@ class CGDescriptor(CGThing):
 
         cgThings.append(CGGeneric(str(properties)))
 
-        if not descriptor.interface.isCallback() and not descriptor.interface.isNamespace():
-            cgThings.append(CGGetProtoObjectMethod(descriptor))
-            reexports.append('GetProtoObject')
-            cgThings.append(CGPrototypeJSClass(descriptor))
-        if descriptor.interface.hasInterfaceObject():
-            if descriptor.interface.ctor():
-                cgThings.append(CGClassConstructHook(descriptor))
-            for ctor in descriptor.interface.namedConstructors:
-                cgThings.append(CGClassConstructHook(descriptor, ctor))
-            if not descriptor.interface.isCallback():
-                cgThings.append(CGInterfaceObjectJSClass(descriptor))
-            if descriptor.shouldHaveGetConstructorObjectMethod():
-                cgThings.append(CGGetConstructorObjectMethod(descriptor))
-                reexports.append('GetConstructorObject')
-            if descriptor.register:
-                cgThings.append(CGDefineDOMInterfaceMethod(descriptor))
-                reexports.append('DefineDOMInterface')
-                cgThings.append(CGConstructorEnabled(descriptor))
-        cgThings.append(CGCreateInterfaceObjectsMethod(descriptor, properties, haveUnscopables))
+        if not descriptor.interface.getExtendedAttribute("Inline"):
+            if not descriptor.interface.isCallback() and not descriptor.interface.isNamespace():
+                cgThings.append(CGGetProtoObjectMethod(descriptor))
+                reexports.append('GetProtoObject')
+                cgThings.append(CGPrototypeJSClass(descriptor))
+            if descriptor.interface.hasInterfaceObject():
+                if descriptor.interface.ctor():
+                    cgThings.append(CGClassConstructHook(descriptor))
+                for ctor in descriptor.interface.namedConstructors:
+                    cgThings.append(CGClassConstructHook(descriptor, ctor))
+                if not descriptor.interface.isCallback():
+                    cgThings.append(CGInterfaceObjectJSClass(descriptor))
+                if descriptor.shouldHaveGetConstructorObjectMethod():
+                    cgThings.append(CGGetConstructorObjectMethod(descriptor))
+                    reexports.append('GetConstructorObject')
+                if descriptor.register:
+                    cgThings.append(CGDefineDOMInterfaceMethod(descriptor))
+                    reexports.append('DefineDOMInterface')
+                    cgThings.append(CGConstructorEnabled(descriptor))
+            cgThings.append(CGCreateInterfaceObjectsMethod(descriptor, properties, haveUnscopables))
 
         cgThings = generate_imports(config, CGList(cgThings, '\n'), [descriptor])
         cgThings = CGWrapper(CGNamespace(toBindingNamespace(descriptor.name),
                                          cgThings, public=True),
                              post='\n')
-        reexports = ', '.join(map(lambda name: reexportedName(name), reexports))
-        self.cgRoot = CGList([CGGeneric('pub use self::%s::{%s};' % (toBindingNamespace(descriptor.name), reexports)),
-                              cgThings], '\n')
+
+        if reexports:
+            reexports = ', '.join(map(lambda name: reexportedName(name), reexports))
+            cgThings = CGList([CGGeneric('pub use self::%s::{%s};' % (toBindingNamespace(descriptor.name), reexports)),
+                               cgThings], '\n')
+
+        self.cgRoot = cgThings
 
     def define(self):
         return self.cgRoot.define()
@@ -6799,7 +6804,7 @@ class GlobalGenRoots():
         globals_ = CGWrapper(CGIndenter(global_flags), pre="bitflags! {\n", post="\n}")
 
         pairs = []
-        for d in config.getDescriptors(hasInterfaceObject=True):
+        for d in config.getDescriptors(hasInterfaceObject=True, isInline=False):
             binding = toBindingNamespace(d.name)
             pairs.append((d.name, binding, binding))
             for ctor in d.interface.namedConstructors:
@@ -6927,7 +6932,7 @@ class GlobalGenRoots():
                 allprotos.append(CGGeneric("\n"))
 
             if downcast:
-                hierarchy[descriptor.getParentName()].append(name)
+                hierarchy[descriptor.interface.parent.identifier.name].append(name)
 
         typeIdCode = []
         topTypeVariants = [
@@ -6959,7 +6964,7 @@ impl Clone for TopTypeId {
 
         for base, derived in hierarchy.iteritems():
             variants = []
-            if not config.getInterface(base).getExtendedAttribute("Abstract"):
+            if config.getDescriptor(base).concrete:
                 variants.append(CGGeneric(base))
             variants += [CGGeneric(type_id_variant(derivedName)) for derivedName in derived]
             derives = "Clone, Copy, Debug, PartialEq"
diff --git a/components/script/dom/bindings/codegen/Configuration.py b/components/script/dom/bindings/codegen/Configuration.py
index 9a1120769c8..f2f64e9bee0 100644
--- a/components/script/dom/bindings/codegen/Configuration.py
+++ b/components/script/dom/bindings/codegen/Configuration.py
@@ -88,6 +88,8 @@ class Configuration:
                 getter = lambda x: x.interface.isJSImplemented()
             elif key == 'isGlobal':
                 getter = lambda x: x.isGlobal()
+            elif key == 'isInline':
+                getter = lambda x: x.interface.getExtendedAttribute('Inline') is not None
             elif key == 'isExposedConditionally':
                 getter = lambda x: x.interface.isExposedConditionally()
             elif key == 'isIteratorInterface':
@@ -234,6 +236,7 @@ class Descriptor(DescriptorProvider):
         self.concrete = (not self.interface.isCallback() and
                          not self.interface.isNamespace() and
                          not self.interface.getExtendedAttribute("Abstract") and
+                         not self.interface.getExtendedAttribute("Inline") and
                          not spiderMonkeyInterface)
         self.hasUnforgeableMembers = (self.concrete and
                                       any(MemberIsUnforgeable(m, self) for m in
@@ -383,8 +386,12 @@ class Descriptor(DescriptorProvider):
         return attrs
 
     def getParentName(self):
-        assert self.interface.parent is not None
-        return self.interface.parent.identifier.name
+        parent = self.interface.parent
+        while parent:
+            if not parent.getExtendedAttribute("Inline"):
+                return parent.identifier.name
+            parent = parent.parent
+        return None
 
     def hasDescendants(self):
         return (self.interface.getUserData("hasConcreteDescendant", False) or
diff --git a/components/script/dom/bindings/codegen/parser/WebIDL.py b/components/script/dom/bindings/codegen/parser/WebIDL.py
index 2894bbeb82e..dc9fa036141 100644
--- a/components/script/dom/bindings/codegen/parser/WebIDL.py
+++ b/components/script/dom/bindings/codegen/parser/WebIDL.py
@@ -1695,7 +1695,8 @@ class IDLInterface(IDLInterfaceOrNamespace):
                   identifier == "ProbablyShortLivingObject" or
                   identifier == "LegacyUnenumerableNamedProperties" or
                   identifier == "NonOrdinaryGetPrototypeOf" or
-                  identifier == "Abstract"):
+                  identifier == "Abstract" or
+                  identifier == "Inline"):
                 # Known extended attributes that do not take values
                 if not attr.noArguments():
                     raise WebIDLError("[%s] must take no arguments" % identifier,
diff --git a/components/script/dom/bindings/codegen/parser/inline.patch b/components/script/dom/bindings/codegen/parser/inline.patch
new file mode 100644
index 00000000000..5d1056d2b58
--- /dev/null
+++ b/components/script/dom/bindings/codegen/parser/inline.patch
@@ -0,0 +1,12 @@
+--- WebIDL.py
++++ WebIDL.py
+@@ -1695,7 +1695,8 @@ class IDLInterface(IDLInterfaceOrNamespace):
+                   identifier == "ProbablyShortLivingObject" or
+                   identifier == "LegacyUnenumerableNamedProperties" or
+                   identifier == "NonOrdinaryGetPrototypeOf" or
+-                  identifier == "Abstract"):
++                  identifier == "Abstract" or
++                  identifier == "Inline"):
+                 # Known extended attributes that do not take values
+                 if not attr.noArguments():
+                     raise WebIDLError("[%s] must take no arguments" % identifier,
\ No newline at end of file
diff --git a/components/script/dom/bindings/codegen/parser/update.sh b/components/script/dom/bindings/codegen/parser/update.sh
index 6bf56cead30..213aba6df89 100755
--- a/components/script/dom/bindings/codegen/parser/update.sh
+++ b/components/script/dom/bindings/codegen/parser/update.sh
@@ -4,6 +4,7 @@ patch < debug.patch
 patch < pref-main-thread.patch
 patch < callback-location.patch
 patch < union-typedef.patch
+patch < inline.patch
 
 wget https://hg.mozilla.org/mozilla-central/archive/tip.tar.gz/dom/bindings/parser/tests/ -O tests.tar.gz
 rm -r tests
diff --git a/components/script/dom/bindings/error.rs b/components/script/dom/bindings/error.rs
index 1c0d49c4976..96ae220ce98 100644
--- a/components/script/dom/bindings/error.rs
+++ b/components/script/dom/bindings/error.rs
@@ -8,9 +8,9 @@ use dom::bindings::codegen::Bindings::DOMExceptionBinding::DOMExceptionMethods;
 use dom::bindings::codegen::PrototypeList::proto_id_to_name;
 use dom::bindings::conversions::{ConversionResult, FromJSValConvertible, ToJSValConvertible};
 use dom::bindings::conversions::root_from_object;
-use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::str::USVString;
 use dom::domexception::{DOMErrorName, DOMException};
+use dom::globalscope::GlobalScope;
 use js::error::{throw_range_error, throw_type_error};
 use js::jsapi::HandleObject;
 use js::jsapi::JSContext;
@@ -87,7 +87,7 @@ pub type Fallible<T> = Result<T, Error>;
 pub type ErrorResult = Fallible<()>;
 
 /// Set a pending exception for the given `result` on `cx`.
-pub unsafe fn throw_dom_exception(cx: *mut JSContext, global: GlobalRef, result: Error) {
+pub unsafe fn throw_dom_exception(cx: *mut JSContext, global: &GlobalScope, result: Error) {
     let code = match result {
         Error::IndexSize => DOMErrorName::IndexSizeError,
         Error::NotFound => DOMErrorName::NotFoundError,
@@ -245,8 +245,8 @@ pub unsafe fn report_pending_exception(cx: *mut JSContext, dispatch_event: bool)
                error_info.message);
 
         if dispatch_event {
-            let global = global_root_from_context(cx);
-            global.r().report_an_error(error_info, value.handle());
+            GlobalScope::from_context(cx)
+                .report_an_error(error_info, value.handle());
         }
     }
 }
@@ -270,7 +270,7 @@ pub unsafe fn throw_invalid_this(cx: *mut JSContext, proto_id: u16) {
 
 impl Error {
     /// Convert this error value to a JS value, consuming it in the process.
-    pub unsafe fn to_jsval(self, cx: *mut JSContext, global: GlobalRef, rval: MutableHandleValue) {
+    pub unsafe fn to_jsval(self, cx: *mut JSContext, global: &GlobalScope, rval: MutableHandleValue) {
         assert!(!JS_IsExceptionPending(cx));
         throw_dom_exception(cx, global, self);
         assert!(JS_IsExceptionPending(cx));
diff --git a/components/script/dom/bindings/global.rs b/components/script/dom/bindings/global.rs
deleted file mode 100644
index e0341ceeb68..00000000000
--- a/components/script/dom/bindings/global.rs
+++ /dev/null
@@ -1,398 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//! Abstractions for global scopes.
-//!
-//! This module contains smart pointers to global scopes, to simplify writing
-//! code that works in workers as well as window scopes.
-
-use devtools_traits::{ScriptToDevtoolsControlMsg, WorkerId};
-use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
-use dom::bindings::conversions::root_from_object;
-use dom::bindings::error::{ErrorInfo, report_pending_exception};
-use dom::bindings::js::Root;
-use dom::bindings::reflector::{Reflectable, Reflector};
-use dom::console::TimerSet;
-use dom::window;
-use dom::workerglobalscope::WorkerGlobalScope;
-use ipc_channel::ipc::IpcSender;
-use js::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
-use js::glue::{IsWrapper, UnwrapObject};
-use js::jsapi::{CurrentGlobalOrNull, Evaluate2, GetGlobalForObjectCrossCompartment};
-use js::jsapi::{HandleValue, JS_GetClass, JSAutoCompartment, JSContext};
-use js::jsapi::{JSObject, MutableHandleValue};
-use js::rust::CompileOptionsWrapper;
-use libc;
-use msg::constellation_msg::PipelineId;
-use net_traits::{CoreResourceThread, IpcSend, ResourceThreads};
-use profile_traits::{mem, time};
-use script_runtime::{CommonScriptMsg, EnqueuedPromiseCallback, ScriptChan};
-use script_runtime::{ScriptPort, maybe_take_panic_result};
-use script_thread::{MainThreadScriptChan, RunnableWrapper, ScriptThread};
-use script_traits::{MsDuration, ScriptMsg as ConstellationMsg, TimerEventRequest};
-use std::ffi::CString;
-use std::panic;
-use task_source::file_reading::FileReadingTaskSource;
-use timers::{OneshotTimerCallback, OneshotTimerHandle};
-use url::Url;
-
-/// A freely-copyable reference to a rooted global object.
-#[derive(Copy, Clone)]
-pub enum GlobalRef<'a> {
-    /// A reference to a `Window` object.
-    Window(&'a window::Window),
-    /// A reference to a `WorkerGlobalScope` object.
-    Worker(&'a WorkerGlobalScope),
-}
-
-/// A stack-based rooted reference to a global object.
-pub enum GlobalRoot {
-    /// A root for a `Window` object.
-    Window(Root<window::Window>),
-    /// A root for a `WorkerGlobalScope` object.
-    Worker(Root<WorkerGlobalScope>),
-}
-
-impl<'a> GlobalRef<'a> {
-    /// Get the `JSContext` for the `JSRuntime` associated with the thread
-    /// this global object is on.
-    pub fn get_cx(&self) -> *mut JSContext {
-        match *self {
-            GlobalRef::Window(ref window) => window.get_cx(),
-            GlobalRef::Worker(ref worker) => worker.get_cx(),
-        }
-    }
-
-    /// Extract a `Window`, causing thread failure if the global object is not
-    /// a `Window`.
-    pub fn as_window(&self) -> &window::Window {
-        match *self {
-            GlobalRef::Window(window) => window,
-            GlobalRef::Worker(_) => panic!("expected a Window scope"),
-        }
-    }
-
-    /// Get the `PipelineId` for this global scope.
-    pub fn pipeline_id(&self) -> PipelineId {
-        match *self {
-            GlobalRef::Window(window) => window.pipeline_id(),
-            GlobalRef::Worker(worker) => worker.pipeline_id(),
-        }
-    }
-
-    /// Get a `mem::ProfilerChan` to send messages to the memory profiler thread.
-    pub fn mem_profiler_chan(&self) -> &mem::ProfilerChan {
-        match *self {
-            GlobalRef::Window(window) => window.mem_profiler_chan(),
-            GlobalRef::Worker(worker) => worker.mem_profiler_chan(),
-        }
-    }
-
-    /// Get a `time::ProfilerChan` to send messages to the time profiler thread.
-    pub fn time_profiler_chan(&self) -> &time::ProfilerChan {
-        match *self {
-            GlobalRef::Window(window) => window.time_profiler_chan(),
-            GlobalRef::Worker(worker) => worker.time_profiler_chan(),
-        }
-    }
-
-    /// Get a `IpcSender` to send messages to the constellation when available.
-    pub fn constellation_chan(&self) -> &IpcSender<ConstellationMsg> {
-        match *self {
-            GlobalRef::Window(window) => window.constellation_chan(),
-            GlobalRef::Worker(worker) => worker.constellation_chan(),
-        }
-    }
-
-    /// Get the scheduler channel to request timer events.
-    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
-        match *self {
-            GlobalRef::Window(window) => window.scheduler_chan(),
-            GlobalRef::Worker(worker) => worker.scheduler_chan(),
-        }
-    }
-
-    /// Get an `IpcSender<ScriptToDevtoolsControlMsg>` to send messages to Devtools
-    /// thread when available.
-    pub fn devtools_chan(&self) -> Option<IpcSender<ScriptToDevtoolsControlMsg>> {
-        match *self {
-            GlobalRef::Window(window) => window.devtools_chan(),
-            GlobalRef::Worker(worker) => worker.devtools_chan(),
-        }
-    }
-
-    /// Get the `ResourceThreads` for this global scope.
-    pub fn resource_threads(&self) -> ResourceThreads {
-        match *self {
-            GlobalRef::Window(ref window) => window.resource_threads().clone(),
-            GlobalRef::Worker(ref worker) => worker.resource_threads().clone(),
-        }
-    }
-
-    /// Get the `CoreResourceThread` for this global scope
-    pub fn core_resource_thread(&self) -> CoreResourceThread {
-        self.resource_threads().sender()
-    }
-
-    /// Get next worker id.
-    pub fn get_next_worker_id(&self) -> WorkerId {
-        match *self {
-            GlobalRef::Window(ref window) => window.get_next_worker_id(),
-            GlobalRef::Worker(ref worker) => worker.get_next_worker_id(),
-        }
-    }
-
-    /// Get the URL for this global scope.
-    pub fn get_url(&self) -> Url {
-        match *self {
-            GlobalRef::Window(ref window) => window.get_url(),
-            GlobalRef::Worker(ref worker) => worker.get_url().clone(),
-        }
-    }
-
-    /// Get the [base url](https://html.spec.whatwg.org/multipage/#api-base-url)
-    /// for this global scope.
-    pub fn api_base_url(&self) -> Url {
-        match *self {
-            // https://html.spec.whatwg.org/multipage/#script-settings-for-browsing-contexts:api-base-url
-            GlobalRef::Window(ref window) => window.Document().base_url(),
-            // https://html.spec.whatwg.org/multipage/#script-settings-for-workers:api-base-url
-            GlobalRef::Worker(ref worker) => worker.get_url().clone(),
-        }
-    }
-
-    /// `ScriptChan` used to send messages to the event loop of this global's
-    /// thread.
-    pub fn script_chan(&self) -> Box<ScriptChan + Send> {
-        match *self {
-            GlobalRef::Window(ref window) =>
-                MainThreadScriptChan(window.main_thread_script_chan().clone()).clone(),
-            GlobalRef::Worker(ref worker) => worker.script_chan(),
-        }
-    }
-
-    /// `ScriptChan` used to send messages to the event loop of this global's
-    /// thread.
-    pub fn networking_task_source(&self) -> Box<ScriptChan + Send> {
-        match *self {
-            GlobalRef::Window(ref window) => window.networking_task_source(),
-            GlobalRef::Worker(ref worker) => worker.script_chan(),
-        }
-    }
-
-    /// `ScriptChan` used to send messages to the event loop of this global's
-    /// thread.
-    pub fn file_reading_task_source(&self) -> FileReadingTaskSource {
-        match *self {
-            GlobalRef::Window(ref window) => window.file_reading_task_source(),
-            GlobalRef::Worker(ref worker) => worker.file_reading_task_source(),
-        }
-    }
-
-    /// Create a new sender/receiver pair that can be used to implement an on-demand
-    /// event loop. Used for implementing web APIs that require blocking semantics
-    /// without resorting to nested event loops.
-    pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
-        match *self {
-            GlobalRef::Window(ref window) => window.new_script_pair(),
-            GlobalRef::Worker(ref worker) => worker.new_script_pair(),
-        }
-    }
-
-    /// Process a single event as if it were the next event in the thread queue for
-    /// this global.
-    pub fn process_event(&self, msg: CommonScriptMsg) {
-        match *self {
-            GlobalRef::Window(_) => ScriptThread::process_event(msg),
-            GlobalRef::Worker(ref worker) => worker.process_event(msg),
-        }
-    }
-
-    /// Evaluate JS code on this global.
-    pub fn evaluate_js_on_global_with_result(
-            &self, code: &str, rval: MutableHandleValue) {
-        self.evaluate_script_on_global_with_result(code, "", rval)
-    }
-
-    /// Evaluate a JS script on this global.
-    #[allow(unsafe_code)]
-    pub fn evaluate_script_on_global_with_result(
-            &self, code: &str, filename: &str, rval: MutableHandleValue) {
-        let metadata = time::TimerMetadata {
-            url: if filename.is_empty() {
-                self.get_url().as_str().into()
-            } else {
-                filename.into()
-            },
-            iframe: time::TimerMetadataFrameType::RootWindow,
-            incremental: time::TimerMetadataReflowType::FirstReflow,
-        };
-        time::profile(
-            time::ProfilerCategory::ScriptEvaluate,
-            Some(metadata),
-            self.time_profiler_chan().clone(),
-            || {
-                let cx = self.get_cx();
-                let globalhandle = self.reflector().get_jsobject();
-                let code: Vec<u16> = code.encode_utf16().collect();
-                let filename = CString::new(filename).unwrap();
-
-                let _ac = JSAutoCompartment::new(cx, globalhandle.get());
-                let options = CompileOptionsWrapper::new(cx, filename.as_ptr(), 1);
-                unsafe {
-                    if !Evaluate2(cx, options.ptr, code.as_ptr(),
-                                  code.len() as libc::size_t,
-                                  rval) {
-                        debug!("error evaluating JS string");
-                        report_pending_exception(cx, true);
-                    }
-                }
-
-                if let Some(error) = maybe_take_panic_result() {
-                    panic::resume_unwind(error);
-                }
-            }
-        )
-    }
-
-    /// Set the `bool` value to indicate whether developer tools has requested
-    /// updates from the global
-    pub fn set_devtools_wants_updates(&self, send_updates: bool) {
-        match *self {
-            GlobalRef::Window(window) => window.set_devtools_wants_updates(send_updates),
-            GlobalRef::Worker(worker) => worker.set_devtools_wants_updates(send_updates),
-        }
-    }
-
-    /// Schedule the given `callback` to be invoked after at least `duration` milliseconds have
-    /// passed.
-    pub fn schedule_callback(&self,
-                             callback: OneshotTimerCallback,
-                             duration: MsDuration)
-                             -> OneshotTimerHandle {
-        match *self {
-            GlobalRef::Window(window) => window.schedule_callback(callback, duration),
-            GlobalRef::Worker(worker) => worker.schedule_callback(callback, duration),
-        }
-    }
-
-    /// Unschedule a previously-scheduled callback.
-    pub fn unschedule_callback(&self, handle: OneshotTimerHandle) {
-        match *self {
-            GlobalRef::Window(window) => window.unschedule_callback(handle),
-            GlobalRef::Worker(worker) => worker.unschedule_callback(handle),
-        }
-    }
-
-    /// Returns the global's timers for the Console API.
-    pub fn console_timers(&self) -> &TimerSet {
-        match *self {
-            GlobalRef::Window(ref window) => window.console_timers(),
-            GlobalRef::Worker(ref worker) => worker.console_timers(),
-        }
-    }
-
-    /// Returns a wrapper for runnables to ensure they are cancelled if the global
-    /// is being destroyed.
-    pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
-        match *self {
-            GlobalRef::Window(ref window) => window.get_runnable_wrapper(),
-            GlobalRef::Worker(ref worker) => worker.get_runnable_wrapper(),
-        }
-    }
-
-    /// Enqueue a promise callback for subsequent execution.
-    pub fn enqueue_promise_job(&self, job: EnqueuedPromiseCallback) {
-        match *self {
-            GlobalRef::Window(_) => ScriptThread::enqueue_promise_job(job, *self),
-            GlobalRef::Worker(ref worker) => worker.enqueue_promise_job(job),
-        }
-    }
-
-    /// Start the process of executing the pending promise callbacks. They will be invoked
-    /// in FIFO order, synchronously, at some point in the future.
-    pub fn flush_promise_jobs(&self) {
-        match *self {
-            GlobalRef::Window(_) => ScriptThread::flush_promise_jobs(*self),
-            GlobalRef::Worker(ref worker) => worker.flush_promise_jobs(),
-        }
-    }
-
-    /// https://html.spec.whatwg.org/multipage/#report-the-error
-    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
-        match *self {
-            GlobalRef::Window(ref window) => window.report_an_error(error_info, value),
-            GlobalRef::Worker(ref worker) => worker.report_an_error(error_info, value),
-        }
-    }
-}
-
-impl<'a> Reflectable for GlobalRef<'a> {
-    fn reflector(&self) -> &Reflector {
-        match *self {
-            GlobalRef::Window(ref window) => window.reflector(),
-            GlobalRef::Worker(ref worker) => worker.reflector(),
-        }
-    }
-}
-
-impl GlobalRoot {
-    /// Obtain a safe reference to the global object that cannot outlive the
-    /// lifetime of this root.
-    pub fn r(&self) -> GlobalRef {
-        match *self {
-            GlobalRoot::Window(ref window) => GlobalRef::Window(window.r()),
-            GlobalRoot::Worker(ref worker) => GlobalRef::Worker(worker.r()),
-        }
-    }
-}
-
-/// Returns the global object of the realm that the given DOM object's reflector was created in.
-pub fn global_root_from_reflector<T: Reflectable>(reflector: &T) -> GlobalRoot {
-    unsafe { global_root_from_object(*reflector.reflector().get_jsobject()) }
-}
-
-/// Returns the Rust global object from a JS global object.
-#[allow(unrooted_must_root)]
-unsafe fn global_root_from_global(global: *mut JSObject) -> GlobalRoot {
-    assert!(!global.is_null());
-    let clasp = JS_GetClass(global);
-    assert!(((*clasp).flags & (JSCLASS_IS_DOMJSCLASS | JSCLASS_IS_GLOBAL)) != 0);
-    match root_from_object(global) {
-        Ok(window) => return GlobalRoot::Window(window),
-        Err(_) => (),
-    }
-
-    match root_from_object(global) {
-        Ok(worker) => return GlobalRoot::Worker(worker),
-        Err(_) => (),
-    }
-
-    panic!("found DOM global that doesn't unwrap to Window or WorkerGlobalScope")
-}
-
-/// Returns the global object of the realm that the given JS object was created in.
-#[allow(unrooted_must_root)]
-pub unsafe fn global_root_from_object(obj: *mut JSObject) -> GlobalRoot {
-    assert!(!obj.is_null());
-    let global = GetGlobalForObjectCrossCompartment(obj);
-    global_root_from_global(global)
-}
-
-/// Returns the global object for the given JSContext
-#[allow(unrooted_must_root)]
-pub unsafe fn global_root_from_context(cx: *mut JSContext) -> GlobalRoot {
-    let global = CurrentGlobalOrNull(cx);
-    global_root_from_global(global)
-}
-
-/// Returns the global object of the realm that the given JS object was created in,
-/// after unwrapping any wrappers.
-pub unsafe fn global_root_from_object_maybe_wrapped(mut obj: *mut JSObject) -> GlobalRoot {
-    if IsWrapper(obj) {
-        obj = UnwrapObject(obj, /* stopAtWindowProxy = */ 0);
-        assert!(!obj.is_null());
-    }
-    global_root_from_object(obj)
-}
diff --git a/components/script/dom/bindings/iterable.rs b/components/script/dom/bindings/iterable.rs
index 84381b52655..3e6febeeb5d 100644
--- a/components/script/dom/bindings/iterable.rs
+++ b/components/script/dom/bindings/iterable.rs
@@ -10,10 +10,10 @@ use core::nonzero::NonZero;
 use dom::bindings::codegen::Bindings::IterableIteratorBinding::IterableKeyAndValueResult;
 use dom::bindings::codegen::Bindings::IterableIteratorBinding::IterableKeyOrValueResult;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, Reflectable, MutReflectable, reflect_dom_object};
 use dom::bindings::trace::JSTraceable;
+use dom::globalscope::GlobalScope;
 use js::conversions::ToJSValConvertible;
 use js::jsapi::{JSContext, JSObject, MutableHandleValue, MutableHandleObject, HandleValue};
 use js::jsval::UndefinedValue;
@@ -85,7 +85,7 @@ impl<T: Reflectable + JSTraceable + Iterable> IterableIterator<T> {
     /// Create a new iterator instance for the provided iterable DOM interface.
     pub fn new(iterable: &T,
                type_: IteratorType,
-               wrap: fn(*mut JSContext, GlobalRef, Box<IterableIterator<T>>)
+               wrap: fn(*mut JSContext, &GlobalScope, Box<IterableIterator<T>>)
                      -> Root<Self>) -> Root<Self> {
         let iterator = box IterableIterator {
             reflector: Reflector::new(),
@@ -93,8 +93,7 @@ impl<T: Reflectable + JSTraceable + Iterable> IterableIterator<T> {
             iterable: JS::from_ref(iterable),
             index: Cell::new(0),
         };
-        let global = iterable.global();
-        reflect_dom_object(iterator, global.r(), wrap)
+        reflect_dom_object(iterator, &*iterable.global(), wrap)
     }
 
     /// Return the next value from the iterable object.
diff --git a/components/script/dom/bindings/mod.rs b/components/script/dom/bindings/mod.rs
index 013484a47b9..27504efda7c 100644
--- a/components/script/dom/bindings/mod.rs
+++ b/components/script/dom/bindings/mod.rs
@@ -43,8 +43,9 @@
 //! [`Fallible<T>`](error/type.Fallible.html).
 //! Methods that use certain WebIDL types like `any` or `object` will get a
 //! `*mut JSContext` argument prepended to the argument list. Static methods
-//! will be passed a [`GlobalRef`](global/enum.GlobalRef.html) for the relevant
-//! global. This argument comes before the `*mut JSContext` argument, if any.
+//! will be passed a [`&GlobalScope`](../globalscope/struct.GlobalScope.html)
+//! for the relevant global. This argument comes before the `*mut JSContext`
+//! argument, if any.
 //!
 //! Rust reflections of WebIDL operations (methods)
 //! -----------------------------------------------
@@ -79,7 +80,7 @@
 //!
 //! A WebIDL constructor is turned into a static class method named
 //! `Constructor`. The arguments of this method will be the arguments of the
-//! WebIDL constructor, with a `GlobalRef` for the relevant global prepended.
+//! WebIDL constructor, with a `&GlobalScope` for the relevant global prepended.
 //! The return value of the constructor for MyInterface is exactly the same as
 //! that of a method returning an instance of MyInterface. Constructors are
 //! always [allowed to throw](#throwing-exceptions).
@@ -133,7 +134,6 @@ pub mod cell;
 pub mod constant;
 pub mod conversions;
 pub mod error;
-pub mod global;
 pub mod guard;
 pub mod inheritance;
 pub mod interface;
diff --git a/components/script/dom/bindings/reflector.rs b/components/script/dom/bindings/reflector.rs
index d5280712a03..737268bf7d0 100644
--- a/components/script/dom/bindings/reflector.rs
+++ b/components/script/dom/bindings/reflector.rs
@@ -4,19 +4,24 @@
 
 //! The `Reflector` struct.
 
-use dom::bindings::global::{GlobalRef, GlobalRoot, global_root_from_reflector};
+use dom::bindings::conversions::DerivedFrom;
 use dom::bindings::js::Root;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleObject, JSContext, JSObject};
 use std::cell::UnsafeCell;
 use std::ptr;
 
 /// Create the reflector for a new DOM object and yield ownership to the
 /// reflector.
-pub fn reflect_dom_object<T: Reflectable>(obj: Box<T>,
-                                          global: GlobalRef,
-                                          wrap_fn: fn(*mut JSContext, GlobalRef, Box<T>) -> Root<T>)
-                                          -> Root<T> {
-    wrap_fn(global.get_cx(), global, obj)
+pub fn reflect_dom_object<T, U>(
+        obj: Box<T>,
+        global: &U,
+        wrap_fn: fn(*mut JSContext, &GlobalScope, Box<T>) -> Root<T>)
+        -> Root<T>
+    where T: Reflectable, U: DerivedFrom<GlobalScope>
+{
+    let global_scope = global.upcast();
+    wrap_fn(global_scope.get_cx(), global_scope, obj)
 }
 
 /// A struct to store a reference to the reflector of a DOM object.
@@ -74,9 +79,9 @@ pub trait Reflectable {
     /// Returns the receiver's reflector.
     fn reflector(&self) -> &Reflector;
 
-    /// Returns the global object of the realm that the Reflectable was created in.
-    fn global(&self) -> GlobalRoot where Self: Sized {
-        global_root_from_reflector(self)
+    /// Returns the global scope of the realm that the Reflectable was created in.
+    fn global(&self) -> Root<GlobalScope> where Self: Sized {
+        GlobalScope::from_reflector(self)
     }
 }
 
diff --git a/components/script/dom/bindings/structuredclone.rs b/components/script/dom/bindings/structuredclone.rs
index 21963eec172..405d245c4bb 100644
--- a/components/script/dom/bindings/structuredclone.rs
+++ b/components/script/dom/bindings/structuredclone.rs
@@ -6,7 +6,7 @@
 //! (https://html.spec.whatwg.org/multipage/#safe-passing-of-structured-data).
 
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, MutableHandleValue};
 use js::jsapi::{JSContext, JS_ReadStructuredClone, JS_STRUCTURED_CLONE_VERSION};
 use js::jsapi::{JS_ClearPendingException, JS_WriteStructuredClone};
@@ -60,7 +60,7 @@ impl StructuredCloneData {
     /// Reads a structured clone.
     ///
     /// Panics if `JS_ReadStructuredClone` fails.
-    fn read_clone(global: GlobalRef, data: *mut u64, nbytes: size_t, rval: MutableHandleValue) {
+    fn read_clone(global: &GlobalScope, data: *mut u64, nbytes: size_t, rval: MutableHandleValue) {
         unsafe {
             assert!(JS_ReadStructuredClone(global.get_cx(),
                                            data,
@@ -73,7 +73,7 @@ impl StructuredCloneData {
     }
 
     /// Thunk for the actual `read_clone` method. Resolves proper variant for read_clone.
-    pub fn read(self, global: GlobalRef, rval: MutableHandleValue) {
+    pub fn read(self, global: &GlobalScope, rval: MutableHandleValue) {
         match self {
             StructuredCloneData::Vector(mut vec_msg) => {
                 let nbytes = vec_msg.len();
diff --git a/components/script/dom/blob.rs b/components/script/dom/blob.rs
index aef31efd687..a2ceed8b046 100644
--- a/components/script/dom/blob.rs
+++ b/components/script/dom/blob.rs
@@ -7,10 +7,10 @@ use dom::bindings::codegen::Bindings::BlobBinding;
 use dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
 use dom::bindings::codegen::UnionTypes::BlobOrString;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use encoding::all::UTF_8;
 use encoding::types::{EncoderTrap, Encoding};
 use ipc_channel::ipc;
@@ -79,7 +79,9 @@ pub struct Blob {
 
 impl Blob {
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef, blob_impl: BlobImpl, typeString: String) -> Root<Blob> {
+    pub fn new(
+            global: &GlobalScope, blob_impl: BlobImpl, typeString: String)
+            -> Root<Blob> {
         let boxed_blob = box Blob::new_inherited(blob_impl, typeString);
         reflect_dom_object(boxed_blob, global, BlobBinding::Wrap)
     }
@@ -99,7 +101,6 @@ impl Blob {
     #[allow(unrooted_must_root)]
     fn new_sliced(parent: &Blob, rel_pos: RelativePos,
                   relative_content_type: DOMString) -> Root<Blob> {
-        let global = parent.global();
         let blob_impl = match *parent.blob_impl.borrow() {
             BlobImpl::File(_) => {
                 // Create new parent node
@@ -115,11 +116,11 @@ impl Blob {
             }
         };
 
-        Blob::new(global.r(), blob_impl, relative_content_type.into())
+        Blob::new(&parent.global(), blob_impl, relative_content_type.into())
     }
 
     // https://w3c.github.io/FileAPI/#constructorBlob
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        blobParts: Option<Vec<BlobOrString>>,
                        blobPropertyBag: &BlobBinding::BlobPropertyBag)
                        -> Fallible<Root<Blob>> {
@@ -142,8 +143,7 @@ impl Blob {
                 let (buffer, is_new_buffer) = match *f.cache.borrow() {
                     Some(ref bytes) => (bytes.clone(), false),
                     None => {
-                        let global = self.global();
-                        let bytes = read_file(global.r(), f.id.clone())?;
+                        let bytes = read_file(&self.global(), f.id.clone())?;
                         (bytes, true)
                     }
                 };
@@ -188,6 +188,7 @@ impl Blob {
     /// valid or invalid Blob URL.
     fn promote(&self, set_valid: bool) -> Uuid {
         let mut bytes = vec![];
+        let global_url = self.global().get_url();
 
         match *self.blob_impl.borrow_mut() {
             BlobImpl::Sliced(_, _) => {
@@ -197,8 +198,7 @@ impl Blob {
             }
             BlobImpl::File(ref f) => {
                 if set_valid {
-                    let global = self.global();
-                    let origin = get_blob_origin(&global.r().get_url());
+                    let origin = get_blob_origin(&global_url);
                     let (tx, rx) = ipc::channel().unwrap();
 
                     let msg = FileManagerThreadMsg::ActivateBlobURL(f.id.clone(), tx, origin.clone());
@@ -217,8 +217,7 @@ impl Blob {
             BlobImpl::Memory(ref mut bytes_in) => mem::swap(bytes_in, &mut bytes),
         };
 
-        let global = self.global();
-        let origin = get_blob_origin(&global.r().get_url());
+        let origin = get_blob_origin(&global_url);
 
         let blob_buf = BlobBuf {
             filename: None,
@@ -249,9 +248,7 @@ impl Blob {
     /// Get a FileID representing sliced parent-blob content
     fn create_sliced_url_id(&self, parent_id: &Uuid,
                             rel_pos: &RelativePos, parent_len: u64) -> Uuid {
-        let global = self.global();
-
-        let origin = get_blob_origin(&global.r().get_url());
+        let origin = get_blob_origin(&self.global().get_url());
 
         let (tx, rx) = ipc::channel().unwrap();
         let msg = FileManagerThreadMsg::AddSlicedURLEntry(parent_id.clone(),
@@ -280,8 +277,7 @@ impl Blob {
     /// Cleanups at the time of destruction/closing
     fn clean_up_file_resource(&self) {
         if let BlobImpl::File(ref f) = *self.blob_impl.borrow() {
-            let global = self.global();
-            let origin = get_blob_origin(&global.r().get_url());
+            let origin = get_blob_origin(&self.global().get_url());
 
             let (tx, rx) = ipc::channel().unwrap();
 
@@ -293,7 +289,7 @@ impl Blob {
 
     fn send_to_file_manager(&self, msg: FileManagerThreadMsg) {
         let global = self.global();
-        let resource_threads = global.r().resource_threads();
+        let resource_threads = global.resource_threads();
         let _ = resource_threads.send(CoreResourceMsg::ToFileManager(msg));
     }
 }
@@ -306,7 +302,7 @@ impl Drop for Blob {
     }
 }
 
-fn read_file(global: GlobalRef, id: Uuid) -> Result<Vec<u8>, ()> {
+fn read_file(global: &GlobalScope, id: Uuid) -> Result<Vec<u8>, ()> {
     let resource_threads = global.resource_threads();
     let (chan, recv) = ipc::channel().map_err(|_|())?;
     let origin = get_blob_origin(&global.get_url());
diff --git a/components/script/dom/bluetooth.rs b/components/script/dom/bluetooth.rs
index 42ad4c2730a..863d75bfec4 100644
--- a/components/script/dom/bluetooth.rs
+++ b/components/script/dom/bluetooth.rs
@@ -8,13 +8,13 @@ use dom::bindings::codegen::Bindings::BluetoothBinding::{self, BluetoothMethods,
 use dom::bindings::codegen::Bindings::BluetoothBinding::RequestDeviceOptions;
 use dom::bindings::error::Error::{self, Security, Type};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::bluetoothadvertisingdata::BluetoothAdvertisingData;
 use dom::bluetoothdevice::BluetoothDevice;
 use dom::bluetoothuuid::{BluetoothServiceUUID, BluetoothUUID};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use ipc_channel::ipc::{self, IpcSender};
 use js::conversions::ToJSValConvertible;
@@ -52,16 +52,14 @@ impl Bluetooth {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<Bluetooth> {
+    pub fn new(global: &GlobalScope) -> Root<Bluetooth> {
         reflect_dom_object(box Bluetooth::new_inherited(),
                            global,
                            BluetoothBinding::Wrap)
     }
 
     fn get_bluetooth_thread(&self) -> IpcSender<BluetoothMethodMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().bluetooth_thread()
+        self.global().as_window().bluetooth_thread()
     }
 
     fn request_device(&self, option: &RequestDeviceOptions) -> Fallible<Root<BluetoothDevice>> {
@@ -105,11 +103,12 @@ impl Bluetooth {
         // Step 12-13.
         match device {
             Ok(device) => {
-                let ad_data = BluetoothAdvertisingData::new(self.global().r(),
+                let global = self.global();
+                let ad_data = BluetoothAdvertisingData::new(&global,
                                                             device.appearance,
                                                             device.tx_power,
                                                             device.rssi);
-                Ok(BluetoothDevice::new(self.global().r(),
+                Ok(BluetoothDevice::new(&global,
                                         DOMString::from(device.id),
                                         device.name.map(DOMString::from),
                                         &ad_data))
@@ -271,13 +270,13 @@ fn canonicalize_filter(filter: &BluetoothRequestDeviceFilter) -> Fallible<Blueto
 }
 
 #[allow(unrooted_must_root)]
-pub fn result_to_promise<T: ToJSValConvertible>(global_ref: GlobalRef,
+pub fn result_to_promise<T: ToJSValConvertible>(global: &GlobalScope,
                                                 bluetooth_result: Fallible<T>)
                                                 -> Rc<Promise> {
-    let p = Promise::new(global_ref);
+    let p = Promise::new(global);
     match bluetooth_result {
-        Ok(v) => p.resolve_native(p.global().r().get_cx(), &v),
-        Err(e) => p.reject_error(p.global().r().get_cx(), e),
+        Ok(v) => p.resolve_native(p.global().get_cx(), &v),
+        Err(e) => p.reject_error(p.global().get_cx(), e),
     }
     p
 }
@@ -298,6 +297,6 @@ impl BluetoothMethods for Bluetooth {
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetooth-requestdevice
     fn RequestDevice(&self, option: &RequestDeviceOptions) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.request_device(option))
+        result_to_promise(&self.global(), self.request_device(option))
     }
 }
diff --git a/components/script/dom/bluetoothadvertisingdata.rs b/components/script/dom/bluetoothadvertisingdata.rs
index 6cd77385a26..878f4fe82ec 100644
--- a/components/script/dom/bluetoothadvertisingdata.rs
+++ b/components/script/dom/bluetoothadvertisingdata.rs
@@ -4,9 +4,9 @@
 
 use dom::bindings::codegen::Bindings::BluetoothAdvertisingDataBinding;
 use dom::bindings::codegen::Bindings::BluetoothAdvertisingDataBinding::BluetoothAdvertisingDataMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 
 // https://webbluetoothcg.github.io/web-bluetooth/#bluetoothadvertisingdata
 #[dom_struct]
@@ -30,7 +30,7 @@ impl BluetoothAdvertisingData {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                appearance: Option<u16>,
                txPower: Option<i8>,
                rssi: Option<i8>)
diff --git a/components/script/dom/bluetoothcharacteristicproperties.rs b/components/script/dom/bluetoothcharacteristicproperties.rs
index fd716d72bb5..ccb5a37a6a8 100644
--- a/components/script/dom/bluetoothcharacteristicproperties.rs
+++ b/components/script/dom/bluetoothcharacteristicproperties.rs
@@ -5,9 +5,9 @@
 use dom::bindings::codegen::Bindings::BluetoothCharacteristicPropertiesBinding;
 use dom::bindings::codegen::Bindings::BluetoothCharacteristicPropertiesBinding::
     BluetoothCharacteristicPropertiesMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 
 // https://webbluetoothcg.github.io/web-bluetooth/#characteristicproperties
  #[dom_struct]
@@ -49,7 +49,7 @@ impl BluetoothCharacteristicProperties {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                broadcast: bool,
                read: bool,
                writeWithoutResponse: bool,
diff --git a/components/script/dom/bluetoothdevice.rs b/components/script/dom/bluetoothdevice.rs
index 1508c0382c8..f4348465108 100644
--- a/components/script/dom/bluetoothdevice.rs
+++ b/components/script/dom/bluetoothdevice.rs
@@ -4,12 +4,12 @@
 
 use dom::bindings::codegen::Bindings::BluetoothDeviceBinding;
 use dom::bindings::codegen::Bindings::BluetoothDeviceBinding::BluetoothDeviceMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root, MutHeap, MutNullableHeap};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::bluetoothadvertisingdata::BluetoothAdvertisingData;
 use dom::bluetoothremotegattserver::BluetoothRemoteGATTServer;
+use dom::globalscope::GlobalScope;
 
 // https://webbluetoothcg.github.io/web-bluetooth/#bluetoothdevice
 #[dom_struct]
@@ -35,7 +35,7 @@ impl BluetoothDevice {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                id: DOMString,
                name: Option<DOMString>,
                adData: &BluetoothAdvertisingData)
@@ -66,6 +66,8 @@ impl BluetoothDeviceMethods for BluetoothDevice {
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothdevice-gatt
     fn Gatt(&self) -> Root<BluetoothRemoteGATTServer> {
-        self.gatt.or_init(|| BluetoothRemoteGATTServer::new(self.global().r(), self))
+        self.gatt.or_init(|| {
+            BluetoothRemoteGATTServer::new(&self.global(), self)
+        })
     }
 }
diff --git a/components/script/dom/bluetoothremotegattcharacteristic.rs b/components/script/dom/bluetoothremotegattcharacteristic.rs
index 6b7ba1dcfad..95b26ff66c1 100644
--- a/components/script/dom/bluetoothremotegattcharacteristic.rs
+++ b/components/script/dom/bluetoothremotegattcharacteristic.rs
@@ -14,7 +14,6 @@ use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServerBinding::Bluetoot
 use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServiceBinding::BluetoothRemoteGATTServiceMethods;
 use dom::bindings::error::{ErrorResult, Fallible};
 use dom::bindings::error::Error::{self, InvalidModification, Network, NotSupported, Security};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, DOMString};
@@ -23,6 +22,7 @@ use dom::bluetoothcharacteristicproperties::BluetoothCharacteristicProperties;
 use dom::bluetoothremotegattdescriptor::BluetoothRemoteGATTDescriptor;
 use dom::bluetoothremotegattservice::BluetoothRemoteGATTService;
 use dom::bluetoothuuid::{BluetoothDescriptorUUID, BluetoothUUID};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use ipc_channel::ipc::{self, IpcSender};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
@@ -59,7 +59,7 @@ impl BluetoothRemoteGATTCharacteristic {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                service: &BluetoothRemoteGATTService,
                uuid: DOMString,
                properties: &BluetoothCharacteristicProperties,
@@ -74,9 +74,7 @@ impl BluetoothRemoteGATTCharacteristic {
     }
 
     fn get_bluetooth_thread(&self) -> IpcSender<BluetoothMethodMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().bluetooth_thread()
+        self.global().as_window().bluetooth_thread()
     }
 
     fn get_instance_id(&self) -> String {
@@ -95,7 +93,7 @@ impl BluetoothRemoteGATTCharacteristic {
         let descriptor = receiver.recv().unwrap();
         match descriptor {
             Ok(descriptor) => {
-                Ok(BluetoothRemoteGATTDescriptor::new(self.global().r(),
+                Ok(BluetoothRemoteGATTDescriptor::new(&self.global(),
                                                       self,
                                                       DOMString::from(descriptor.uuid),
                                                       descriptor.instance_id))
@@ -126,7 +124,7 @@ impl BluetoothRemoteGATTCharacteristic {
         match descriptors_vec {
             Ok(descriptor_vec) => {
                 Ok(descriptor_vec.into_iter()
-                                 .map(|desc| BluetoothRemoteGATTDescriptor::new(self.global().r(),
+                                 .map(|desc| BluetoothRemoteGATTDescriptor::new(&self.global(),
                                                                                 self,
                                                                                 DOMString::from(desc.uuid),
                                                                                 desc.instance_id))
@@ -214,7 +212,7 @@ impl BluetoothRemoteGATTCharacteristicMethods for BluetoothRemoteGATTCharacteris
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattcharacteristic-getdescriptor
     fn GetDescriptor(&self, descriptor: BluetoothDescriptorUUID) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_descriptor(descriptor))
+        result_to_promise(&self.global(), self.get_descriptor(descriptor))
     }
 
     #[allow(unrooted_must_root)]
@@ -222,7 +220,7 @@ impl BluetoothRemoteGATTCharacteristicMethods for BluetoothRemoteGATTCharacteris
     fn GetDescriptors(&self,
                       descriptor: Option<BluetoothDescriptorUUID>)
                       -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_descriptors(descriptor))
+        result_to_promise(&self.global(), self.get_descriptors(descriptor))
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattcharacteristic-value
@@ -233,12 +231,12 @@ impl BluetoothRemoteGATTCharacteristicMethods for BluetoothRemoteGATTCharacteris
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattcharacteristic-readvalue
     fn ReadValue(&self) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.read_value())
+        result_to_promise(&self.global(), self.read_value())
     }
 
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattcharacteristic-writevalue
     fn WriteValue(&self, value: Vec<u8>) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.write_value(value))
+        result_to_promise(&self.global(), self.write_value(value))
     }
 }
diff --git a/components/script/dom/bluetoothremotegattdescriptor.rs b/components/script/dom/bluetoothremotegattdescriptor.rs
index d036f8bd9ea..f066bb9d22a 100644
--- a/components/script/dom/bluetoothremotegattdescriptor.rs
+++ b/components/script/dom/bluetoothremotegattdescriptor.rs
@@ -13,12 +13,12 @@ use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServerBinding::Bluetoot
 use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServiceBinding::BluetoothRemoteGATTServiceMethods;
 use dom::bindings::error::{ErrorResult, Fallible};
 use dom::bindings::error::Error::{self, InvalidModification, Network, Security};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, DOMString};
 use dom::bluetooth::result_to_promise;
 use dom::bluetoothremotegattcharacteristic::{BluetoothRemoteGATTCharacteristic, MAXIMUM_ATTRIBUTE_LENGTH};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use ipc_channel::ipc::{self, IpcSender};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
@@ -48,7 +48,7 @@ impl BluetoothRemoteGATTDescriptor {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                characteristic: &BluetoothRemoteGATTCharacteristic,
                uuid: DOMString,
                instanceID: String)
@@ -61,9 +61,7 @@ impl BluetoothRemoteGATTDescriptor {
     }
 
     fn get_bluetooth_thread(&self) -> IpcSender<BluetoothMethodMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().bluetooth_thread()
+        self.global().as_window().bluetooth_thread()
     }
 
     fn get_instance_id(&self) -> String {
@@ -137,12 +135,12 @@ impl BluetoothRemoteGATTDescriptorMethods for BluetoothRemoteGATTDescriptor {
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-readvalue
     fn ReadValue(&self) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.read_value())
+        result_to_promise(&self.global(), self.read_value())
     }
 
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-writevalue
     fn WriteValue(&self, value: Vec<u8>) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.write_value(value))
+        result_to_promise(&self.global(), self.write_value(value))
     }
 }
diff --git a/components/script/dom/bluetoothremotegattserver.rs b/components/script/dom/bluetoothremotegattserver.rs
index 3439ba53350..fe19651ebf4 100644
--- a/components/script/dom/bluetoothremotegattserver.rs
+++ b/components/script/dom/bluetoothremotegattserver.rs
@@ -8,7 +8,6 @@ use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServerBinding;
 use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServerBinding::BluetoothRemoteGATTServerMethods;
 use dom::bindings::error::{ErrorResult, Fallible};
 use dom::bindings::error::Error::{self, Security};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -16,6 +15,7 @@ use dom::bluetooth::result_to_promise;
 use dom::bluetoothdevice::BluetoothDevice;
 use dom::bluetoothremotegattservice::BluetoothRemoteGATTService;
 use dom::bluetoothuuid::{BluetoothServiceUUID, BluetoothUUID};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use ipc_channel::ipc::{self, IpcSender};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
@@ -39,16 +39,14 @@ impl BluetoothRemoteGATTServer {
         }
     }
 
-    pub fn new(global: GlobalRef, device: &BluetoothDevice) -> Root<BluetoothRemoteGATTServer> {
+    pub fn new(global: &GlobalScope, device: &BluetoothDevice) -> Root<BluetoothRemoteGATTServer> {
         reflect_dom_object(box BluetoothRemoteGATTServer::new_inherited(device),
-        global,
-        BluetoothRemoteGATTServerBinding::Wrap)
+                           global,
+                           BluetoothRemoteGATTServerBinding::Wrap)
     }
 
     fn get_bluetooth_thread(&self) -> IpcSender<BluetoothMethodMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().bluetooth_thread()
+        self.global().as_window().bluetooth_thread()
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattserver-connect
@@ -80,7 +78,7 @@ impl BluetoothRemoteGATTServer {
         let service = receiver.recv().unwrap();
         match service {
             Ok(service) => {
-                Ok(BluetoothRemoteGATTService::new(self.global().r(),
+                Ok(BluetoothRemoteGATTService::new(&self.global(),
                                                    &self.device.get(),
                                                    DOMString::from(service.uuid),
                                                    service.is_primary,
@@ -112,7 +110,7 @@ impl BluetoothRemoteGATTServer {
         match services_vec {
             Ok(service_vec) => {
                 Ok(service_vec.into_iter()
-                              .map(|service| BluetoothRemoteGATTService::new(self.global().r(),
+                              .map(|service| BluetoothRemoteGATTService::new(&self.global(),
                                                                              &self.device.get(),
                                                                              DOMString::from(service.uuid),
                                                                              service.is_primary,
@@ -140,7 +138,7 @@ impl BluetoothRemoteGATTServerMethods for BluetoothRemoteGATTServer {
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattserver-connect
     fn Connect(&self) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.connect())
+        result_to_promise(&self.global(), self.connect())
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattserver-disconnect
@@ -163,7 +161,7 @@ impl BluetoothRemoteGATTServerMethods for BluetoothRemoteGATTServer {
     #[allow(unrooted_must_root)]
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattserver-getprimaryservice
     fn GetPrimaryService(&self, service: BluetoothServiceUUID) -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_primary_service(service))
+        result_to_promise(&self.global(), self.get_primary_service(service))
     }
 
     #[allow(unrooted_must_root)]
@@ -171,6 +169,6 @@ impl BluetoothRemoteGATTServerMethods for BluetoothRemoteGATTServer {
     fn GetPrimaryServices(&self,
                           service: Option<BluetoothServiceUUID>)
                           -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_primary_services(service))
+        result_to_promise(&self.global(), self.get_primary_services(service))
     }
 }
diff --git a/components/script/dom/bluetoothremotegattservice.rs b/components/script/dom/bluetoothremotegattservice.rs
index 3ece2507cd3..bce51131649 100644
--- a/components/script/dom/bluetoothremotegattservice.rs
+++ b/components/script/dom/bluetoothremotegattservice.rs
@@ -7,7 +7,6 @@ use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServiceBinding;
 use dom::bindings::codegen::Bindings::BluetoothRemoteGATTServiceBinding::BluetoothRemoteGATTServiceMethods;
 use dom::bindings::error::Error::{self, Security};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -16,6 +15,7 @@ use dom::bluetoothcharacteristicproperties::BluetoothCharacteristicProperties;
 use dom::bluetoothdevice::BluetoothDevice;
 use dom::bluetoothremotegattcharacteristic::BluetoothRemoteGATTCharacteristic;
 use dom::bluetoothuuid::{BluetoothCharacteristicUUID, BluetoothServiceUUID, BluetoothUUID};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use ipc_channel::ipc::{self, IpcSender};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
@@ -46,7 +46,7 @@ impl BluetoothRemoteGATTService {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                device: &BluetoothDevice,
                uuid: DOMString,
                isPrimary: bool,
@@ -61,9 +61,7 @@ impl BluetoothRemoteGATTService {
     }
 
     fn get_bluetooth_thread(&self) -> IpcSender<BluetoothMethodMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().bluetooth_thread()
+        self.global().as_window().bluetooth_thread()
     }
 
     fn get_instance_id(&self) -> String {
@@ -84,7 +82,8 @@ impl BluetoothRemoteGATTService {
         let characteristic = receiver.recv().unwrap();
         match characteristic {
             Ok(characteristic) => {
-                let properties = BluetoothCharacteristicProperties::new(self.global().r(),
+                let global = self.global();
+                let properties = BluetoothCharacteristicProperties::new(&global,
                                                                         characteristic.broadcast,
                                                                         characteristic.read,
                                                                         characteristic.write_without_response,
@@ -94,7 +93,7 @@ impl BluetoothRemoteGATTService {
                                                                         characteristic.authenticated_signed_writes,
                                                                         characteristic.reliable_write,
                                                                         characteristic.writable_auxiliaries);
-                Ok(BluetoothRemoteGATTCharacteristic::new(self.global().r(),
+                Ok(BluetoothRemoteGATTCharacteristic::new(&global,
                                                           self,
                                                           DOMString::from(characteristic.uuid),
                                                           &properties,
@@ -127,7 +126,8 @@ impl BluetoothRemoteGATTService {
         match characteristics_vec {
             Ok(characteristic_vec) => {
                 for characteristic in characteristic_vec {
-                    let properties = BluetoothCharacteristicProperties::new(self.global().r(),
+                    let global = self.global();
+                    let properties = BluetoothCharacteristicProperties::new(&global,
                                                                             characteristic.broadcast,
                                                                             characteristic.read,
                                                                             characteristic.write_without_response,
@@ -137,7 +137,7 @@ impl BluetoothRemoteGATTService {
                                                                             characteristic.authenticated_signed_writes,
                                                                             characteristic.reliable_write,
                                                                             characteristic.writable_auxiliaries);
-                    characteristics.push(BluetoothRemoteGATTCharacteristic::new(self.global().r(),
+                    characteristics.push(BluetoothRemoteGATTCharacteristic::new(&global,
                                                                                 self,
                                                                                 DOMString::from(characteristic.uuid),
                                                                                 &properties,
@@ -167,7 +167,7 @@ impl BluetoothRemoteGATTService {
         let service = receiver.recv().unwrap();
         match service {
             Ok(service) => {
-                Ok(BluetoothRemoteGATTService::new(self.global().r(),
+                Ok(BluetoothRemoteGATTService::new(&self.global(),
                                                    &self.device.get(),
                                                    DOMString::from(service.uuid),
                                                    service.is_primary,
@@ -201,7 +201,7 @@ impl BluetoothRemoteGATTService {
         match services_vec {
             Ok(service_vec) => {
                 Ok(service_vec.into_iter()
-                              .map(|service| BluetoothRemoteGATTService::new(self.global().r(),
+                              .map(|service| BluetoothRemoteGATTService::new(&self.global(),
                                                                              &self.device.get(),
                                                                              DOMString::from(service.uuid),
                                                                              service.is_primary,
@@ -236,7 +236,7 @@ impl BluetoothRemoteGATTServiceMethods for BluetoothRemoteGATTService {
     fn GetCharacteristic(&self,
                          characteristic: BluetoothCharacteristicUUID)
                          -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_characteristic(characteristic))
+        result_to_promise(&self.global(), self.get_characteristic(characteristic))
     }
 
     #[allow(unrooted_must_root)]
@@ -244,7 +244,7 @@ impl BluetoothRemoteGATTServiceMethods for BluetoothRemoteGATTService {
     fn GetCharacteristics(&self,
                           characteristic: Option<BluetoothCharacteristicUUID>)
                           -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_characteristics(characteristic))
+        result_to_promise(&self.global(), self.get_characteristics(characteristic))
     }
 
     #[allow(unrooted_must_root)]
@@ -252,7 +252,7 @@ impl BluetoothRemoteGATTServiceMethods for BluetoothRemoteGATTService {
     fn GetIncludedService(&self,
                           service: BluetoothServiceUUID)
                           -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_included_service(service))
+        result_to_promise(&self.global(), self.get_included_service(service))
     }
 
     #[allow(unrooted_must_root)]
@@ -260,6 +260,6 @@ impl BluetoothRemoteGATTServiceMethods for BluetoothRemoteGATTService {
     fn GetIncludedServices(&self,
                           service: Option<BluetoothServiceUUID>)
                           -> Rc<Promise> {
-        result_to_promise(self.global().r(), self.get_included_services(service))
+        result_to_promise(&self.global(), self.get_included_services(service))
     }
 }
diff --git a/components/script/dom/bluetoothuuid.rs b/components/script/dom/bluetoothuuid.rs
index e9669cc8acb..11fb7af94cb 100644
--- a/components/script/dom/bluetoothuuid.rs
+++ b/components/script/dom/bluetoothuuid.rs
@@ -5,9 +5,9 @@
 use dom::bindings::codegen::UnionTypes::StringOrUnsignedLong;
 use dom::bindings::error::Error::Syntax;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::reflector::Reflector;
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use regex::Regex;
 
 pub type UUID = DOMString;
@@ -271,22 +271,22 @@ const VALID_UUID_REGEX: &'static str = "^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-
 
 impl BluetoothUUID {
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothuuid-canonicaluuid
-    pub fn CanonicalUUID(_: GlobalRef, alias: u32) -> UUID {
+    pub fn CanonicalUUID(_: &GlobalScope, alias: u32) -> UUID {
         canonical_uuid(alias)
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothuuid-getservice
-    pub fn GetService(_: GlobalRef, name: BluetoothServiceUUID) -> Fallible<UUID> {
+    pub fn GetService(_: &GlobalScope, name: BluetoothServiceUUID) -> Fallible<UUID> {
         Self::service(name)
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothuuid-getcharacteristic
-    pub fn GetCharacteristic(_: GlobalRef, name: BluetoothCharacteristicUUID) -> Fallible<UUID> {
+    pub fn GetCharacteristic(_: &GlobalScope, name: BluetoothCharacteristicUUID) -> Fallible<UUID> {
         Self::characteristic(name)
     }
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothuuid-getdescriptor
-    pub fn GetDescriptor(_: GlobalRef, name: BluetoothDescriptorUUID) -> Fallible<UUID> {
+    pub fn GetDescriptor(_: &GlobalScope, name: BluetoothDescriptorUUID) -> Fallible<UUID> {
         Self::descriptor(name)
     }
 }
diff --git a/components/script/dom/browsingcontext.rs b/components/script/dom/browsingcontext.rs
index 9f867157fab..2ea6a1b78bd 100644
--- a/components/script/dom/browsingcontext.rs
+++ b/components/script/dom/browsingcontext.rs
@@ -4,6 +4,7 @@
 
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::conversions::{ToJSValConvertible, root_from_handleobject};
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::proxyhandler::{fill_property_descriptor, get_property_descriptor};
 use dom::bindings::reflector::{Reflectable, MutReflectable, Reflector};
@@ -12,6 +13,7 @@ use dom::bindings::utils::WindowProxyHandler;
 use dom::bindings::utils::get_array_index_from_id;
 use dom::document::Document;
 use dom::element::Element;
+use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use js::JSCLASS_IS_GLOBAL;
 use js::glue::{CreateWrapperProxyHandler, ProxyTraps, NewWindowProxy};
@@ -150,7 +152,7 @@ impl BrowsingContext {
     pub fn find_child_by_id(&self, pipeline_id: PipelineId) -> Option<Root<Window>> {
         self.children.borrow().iter().find(|context| {
             let window = context.active_window();
-            window.pipeline_id() == pipeline_id
+            window.upcast::<GlobalScope>().pipeline_id() == pipeline_id
         }).map(|context| context.active_window())
     }
 
diff --git a/components/script/dom/canvasgradient.rs b/components/script/dom/canvasgradient.rs
index a805b485796..0fafc1c6f0f 100644
--- a/components/script/dom/canvasgradient.rs
+++ b/components/script/dom/canvasgradient.rs
@@ -9,11 +9,11 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::CanvasGradientBinding;
 use dom::bindings::codegen::Bindings::CanvasGradientBinding::CanvasGradientMethods;
 use dom::bindings::error::{Error, ErrorResult};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::num::Finite;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 // https://html.spec.whatwg.org/multipage/#canvasgradient
 #[dom_struct]
@@ -38,7 +38,7 @@ impl CanvasGradient {
         }
     }
 
-    pub fn new(global: GlobalRef, style: CanvasGradientStyle) -> Root<CanvasGradient> {
+    pub fn new(global: &GlobalScope, style: CanvasGradientStyle) -> Root<CanvasGradient> {
         reflect_dom_object(box CanvasGradient::new_inherited(style),
                            global,
                            CanvasGradientBinding::Wrap)
diff --git a/components/script/dom/canvaspattern.rs b/components/script/dom/canvaspattern.rs
index 059710a296b..5fdb911c73a 100644
--- a/components/script/dom/canvaspattern.rs
+++ b/components/script/dom/canvaspattern.rs
@@ -4,10 +4,10 @@
 
 use canvas_traits::{FillOrStrokeStyle, RepetitionStyle, SurfaceStyle};
 use dom::bindings::codegen::Bindings::CanvasPatternBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::canvasgradient::ToFillOrStrokeStyle;
+use dom::globalscope::GlobalScope;
 use euclid::size::Size2D;
 
 // https://html.spec.whatwg.org/multipage/#canvaspattern
@@ -43,7 +43,7 @@ impl CanvasPattern {
             origin_clean: origin_clean,
         }
     }
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                surface_data: Vec<u8>,
                surface_size: Size2D<i32>,
                repeat: RepetitionStyle,
diff --git a/components/script/dom/canvasrenderingcontext2d.rs b/components/script/dom/canvasrenderingcontext2d.rs
index 4b598407829..f2436f73419 100644
--- a/components/script/dom/canvasrenderingcontext2d.rs
+++ b/components/script/dom/canvasrenderingcontext2d.rs
@@ -20,7 +20,6 @@ use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::UnionTypes::HTMLImageElementOrHTMLCanvasElementOrCanvasRenderingContext2D;
 use dom::bindings::codegen::UnionTypes::StringOrCanvasGradientOrCanvasPattern;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, LayoutJS, Root};
 use dom::bindings::num::Finite;
@@ -28,6 +27,7 @@ use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::canvasgradient::{CanvasGradient, CanvasGradientStyle, ToFillOrStrokeStyle};
 use dom::canvaspattern::CanvasPattern;
+use dom::globalscope::GlobalScope;
 use dom::htmlcanvaselement::HTMLCanvasElement;
 use dom::htmlcanvaselement::utils as canvas_utils;
 use dom::htmlimageelement::HTMLImageElement;
@@ -117,7 +117,7 @@ impl CanvasContextState {
 }
 
 impl CanvasRenderingContext2D {
-    fn new_inherited(global: GlobalRef,
+    fn new_inherited(global: &GlobalScope,
                      canvas: &HTMLCanvasElement,
                      size: Size2D<i32>)
                      -> CanvasRenderingContext2D {
@@ -135,7 +135,7 @@ impl CanvasRenderingContext2D {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                canvas: &HTMLCanvasElement,
                size: Size2D<i32>)
                -> Root<CanvasRenderingContext2D> {
@@ -1016,12 +1016,12 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
 
         let sw = cmp::max(1, sw.abs().to_u32().unwrap());
         let sh = cmp::max(1, sh.abs().to_u32().unwrap());
-        Ok(ImageData::new(self.global().r(), sw, sh, None))
+        Ok(ImageData::new(&self.global(), sw, sh, None))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-context-2d-createimagedata
     fn CreateImageData_(&self, imagedata: &ImageData) -> Fallible<Root<ImageData>> {
-        Ok(ImageData::new(self.global().r(),
+        Ok(ImageData::new(&self.global(),
                           imagedata.Width(),
                           imagedata.Height(),
                           None))
@@ -1077,7 +1077,7 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
             chunk[2] = UNPREMULTIPLY_TABLE[256 * alpha + chunk[2] as usize];
         }
 
-        Ok(ImageData::new(self.global().r(), sw, sh, Some(data)))
+        Ok(ImageData::new(&self.global(), sw, sh, Some(data)))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-context-2d-putimagedata
@@ -1121,7 +1121,7 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
                             x1: Finite<f64>,
                             y1: Finite<f64>)
                             -> Root<CanvasGradient> {
-        CanvasGradient::new(self.global().r(),
+        CanvasGradient::new(&self.global(),
                             CanvasGradientStyle::Linear(LinearGradientStyle::new(*x0,
                                                                                  *y0,
                                                                                  *x1,
@@ -1142,7 +1142,7 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
             return Err(Error::IndexSize);
         }
 
-        Ok(CanvasGradient::new(self.global().r(),
+        Ok(CanvasGradient::new(&self.global(),
                                CanvasGradientStyle::Radial(RadialGradientStyle::new(*x0,
                                                                                     *y0,
                                                                                     *r0,
@@ -1182,7 +1182,7 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
         }
 
         if let Ok(rep) = RepetitionStyle::from_str(&repetition) {
-            Ok(CanvasPattern::new(self.global().r(),
+            Ok(CanvasPattern::new(&self.global(),
                                   image_data,
                                   image_size,
                                   rep,
diff --git a/components/script/dom/client.rs b/components/script/dom/client.rs
index 74ed61a52a7..7f51b251627 100644
--- a/components/script/dom/client.rs
+++ b/components/script/dom/client.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::ClientBinding::{ClientMethods, Wrap};
 use dom::bindings::codegen::Bindings::ClientBinding::FrameType;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::JS;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -36,7 +35,9 @@ impl Client {
     }
 
     pub fn new(window: &Window) -> Root<Client> {
-        reflect_dom_object(box Client::new_inherited(window.get_url()), GlobalRef::Window(window), Wrap)
+        reflect_dom_object(box Client::new_inherited(window.get_url()),
+                           window,
+                           Wrap)
     }
 }
 
diff --git a/components/script/dom/closeevent.rs b/components/script/dom/closeevent.rs
index 07e2fbaa943..a66af7bd75f 100644
--- a/components/script/dom/closeevent.rs
+++ b/components/script/dom/closeevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::CloseEventBinding;
 use dom::bindings::codegen::Bindings::CloseEventBinding::CloseEventMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use string_cache::Atom;
 
 #[dom_struct]
@@ -32,13 +32,13 @@ impl CloseEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<CloseEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<CloseEvent> {
         reflect_dom_object(box CloseEvent::new_inherited(false, 0, DOMString::new()),
                            global,
                            CloseEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable,
@@ -57,7 +57,7 @@ impl CloseEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &CloseEventBinding::CloseEventInit)
                        -> Fallible<Root<CloseEvent>> {
diff --git a/components/script/dom/comment.rs b/components/script/dom/comment.rs
index 43115e1dd51..875544202d7 100644
--- a/components/script/dom/comment.rs
+++ b/components/script/dom/comment.rs
@@ -5,11 +5,11 @@
 use dom::bindings::codegen::Bindings::CommentBinding;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::str::DOMString;
 use dom::characterdata::CharacterData;
 use dom::document::Document;
+use dom::globalscope::GlobalScope;
 use dom::node::Node;
 
 /// An HTML comment.
@@ -31,7 +31,7 @@ impl Comment {
                            CommentBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef, data: DOMString) -> Fallible<Root<Comment>> {
+    pub fn Constructor(global: &GlobalScope, data: DOMString) -> Fallible<Root<Comment>> {
         let document = global.as_window().Document();
         Ok(Comment::new(data, document.r()))
     }
diff --git a/components/script/dom/console.rs b/components/script/dom/console.rs
index ad28c585248..d9df56ebef0 100644
--- a/components/script/dom/console.rs
+++ b/components/script/dom/console.rs
@@ -3,25 +3,21 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use devtools_traits::{ConsoleMessage, LogLevel, ScriptToDevtoolsControlMsg};
-use dom::bindings::cell::DOMRefCell;
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::str::DOMString;
-use std::collections::HashMap;
-use std::collections::hash_map::Entry;
-use time::{Timespec, get_time};
+use dom::globalscope::GlobalScope;
+use dom::workerglobalscope::WorkerGlobalScope;
 
 // https://developer.mozilla.org/en-US/docs/Web/API/Console
 pub struct Console(());
 
 impl Console {
-    fn send_to_devtools(global: GlobalRef, level: LogLevel, message: DOMString) {
+    fn send_to_devtools(global: &GlobalScope, level: LogLevel, message: DOMString) {
         if let Some(chan) = global.devtools_chan() {
             let console_message = prepare_message(level, message);
-            let worker_id = if let GlobalRef::Worker(worker) = global {
-                Some(worker.get_worker_id())
-            } else {
-                None
-            };
+            let worker_id = global.downcast::<WorkerGlobalScope>().map(|worker| {
+                worker.get_worker_id()
+            });
             let devtools_message = ScriptToDevtoolsControlMsg::ConsoleAPI(
                 global.pipeline_id(),
                 console_message,
@@ -33,7 +29,7 @@ impl Console {
 
 impl Console {
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/log
-    pub fn Log(global: GlobalRef, messages: Vec<DOMString>) {
+    pub fn Log(global: &GlobalScope, messages: Vec<DOMString>) {
         for message in messages {
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Log, message);
@@ -41,7 +37,7 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console
-    pub fn Debug(global: GlobalRef, messages: Vec<DOMString>) {
+    pub fn Debug(global: &GlobalScope, messages: Vec<DOMString>) {
         for message in messages {
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Debug, message);
@@ -49,7 +45,7 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/info
-    pub fn Info(global: GlobalRef, messages: Vec<DOMString>) {
+    pub fn Info(global: &GlobalScope, messages: Vec<DOMString>) {
         for message in messages {
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Info, message);
@@ -57,7 +53,7 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/warn
-    pub fn Warn(global: GlobalRef, messages: Vec<DOMString>) {
+    pub fn Warn(global: &GlobalScope, messages: Vec<DOMString>) {
         for message in messages {
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Warn, message);
@@ -65,7 +61,7 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/error
-    pub fn Error(global: GlobalRef, messages: Vec<DOMString>) {
+    pub fn Error(global: &GlobalScope, messages: Vec<DOMString>) {
         for message in messages {
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Error, message);
@@ -73,7 +69,7 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/assert
-    pub fn Assert(global: GlobalRef, condition: bool, message: Option<DOMString>) {
+    pub fn Assert(global: &GlobalScope, condition: bool, message: Option<DOMString>) {
         if !condition {
             let message = message.unwrap_or_else(|| DOMString::from("no message"));
             println!("Assertion failed: {}", message);
@@ -82,8 +78,8 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/time
-    pub fn Time(global: GlobalRef, label: DOMString) {
-        if let Ok(()) = global.console_timers().time(label.clone()) {
+    pub fn Time(global: &GlobalScope, label: DOMString) {
+        if let Ok(()) = global.time(label.clone()) {
             let message = DOMString::from(format!("{}: timer started", label));
             println!("{}", message);
             Self::send_to_devtools(global, LogLevel::Log, message);
@@ -91,8 +87,8 @@ impl Console {
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/Console/timeEnd
-    pub fn TimeEnd(global: GlobalRef, label: DOMString) {
-        if let Ok(delta) = global.console_timers().time_end(&label) {
+    pub fn TimeEnd(global: &GlobalScope, label: DOMString) {
+        if let Ok(delta) = global.time_end(&label) {
             let message = DOMString::from(
                 format!("{}: {}ms", label, delta)
             );
@@ -102,10 +98,6 @@ impl Console {
     }
 }
 
-fn timestamp_in_ms(time: Timespec) -> u64 {
-    (time.sec * 1000 + (time.nsec / 1000000) as i64) as u64
-}
-
 fn prepare_message(log_level: LogLevel, message: DOMString) -> ConsoleMessage {
     // TODO: Sending fake values for filename, lineNumber and columnNumber in LogMessage; adjust later
     ConsoleMessage {
@@ -116,32 +108,3 @@ fn prepare_message(log_level: LogLevel, message: DOMString) -> ConsoleMessage {
         columnNumber: 1,
     }
 }
-
-#[derive(HeapSizeOf, JSTraceable)]
-pub struct TimerSet(DOMRefCell<HashMap<DOMString, u64>>);
-
-impl TimerSet {
-    pub fn new() -> Self {
-        TimerSet(DOMRefCell::new(Default::default()))
-    }
-
-    fn time(&self, label: DOMString) -> Result<(), ()> {
-        let mut timers = self.0.borrow_mut();
-        if timers.len() >= 10000 {
-            return Err(());
-        }
-        match timers.entry(label) {
-            Entry::Vacant(entry) => {
-                entry.insert(timestamp_in_ms(get_time()));
-                Ok(())
-            },
-            Entry::Occupied(_) => Err(()),
-        }
-    }
-
-    fn time_end(&self, label: &str) -> Result<u64, ()> {
-        self.0.borrow_mut().remove(label).ok_or(()).map(|start| {
-            timestamp_in_ms(get_time()) - start
-        })
-    }
-}
diff --git a/components/script/dom/crypto.rs b/components/script/dom/crypto.rs
index 165a3834227..45c1c4639d5 100644
--- a/components/script/dom/crypto.rs
+++ b/components/script/dom/crypto.rs
@@ -8,9 +8,9 @@ use dom::bindings::codegen::Bindings::CryptoBinding;
 use dom::bindings::codegen::Bindings::CryptoBinding::CryptoMethods;
 use dom::bindings::conversions::array_buffer_view_data;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use js::jsapi::{JSContext, JSObject};
 use js::jsapi::{JS_GetArrayBufferViewType, Type};
 use rand::{OsRng, Rng};
@@ -33,7 +33,7 @@ impl Crypto {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<Crypto> {
+    pub fn new(global: &GlobalScope) -> Root<Crypto> {
         reflect_dom_object(box Crypto::new_inherited(), global, CryptoBinding::Wrap)
     }
 }
diff --git a/components/script/dom/css.rs b/components/script/dom/css.rs
index 105de8ec9c1..f2256007aeb 100644
--- a/components/script/dom/css.rs
+++ b/components/script/dom/css.rs
@@ -4,9 +4,9 @@
 
 use cssparser::serialize_identifier;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::reflector::Reflector;
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct CSS {
@@ -15,7 +15,7 @@ pub struct CSS {
 
 impl CSS {
     // http://dev.w3.org/csswg/cssom/#serialize-an-identifier
-    pub fn Escape(_: GlobalRef, ident: DOMString) -> Fallible<DOMString> {
+    pub fn Escape(_: &GlobalScope, ident: DOMString) -> Fallible<DOMString> {
         let mut escaped = String::new();
         serialize_identifier(&ident, &mut escaped).unwrap();
         Ok(DOMString::from(escaped))
diff --git a/components/script/dom/cssstyledeclaration.rs b/components/script/dom/cssstyledeclaration.rs
index 0b8c9d8a062..77aee91ce48 100644
--- a/components/script/dom/cssstyledeclaration.rs
+++ b/components/script/dom/cssstyledeclaration.rs
@@ -5,7 +5,6 @@
 use cssparser::ToCss;
 use dom::bindings::codegen::Bindings::CSSStyleDeclarationBinding::{self, CSSStyleDeclarationMethods};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -71,7 +70,7 @@ impl CSSStyleDeclaration {
         reflect_dom_object(box CSSStyleDeclaration::new_inherited(owner,
                                                                   pseudo,
                                                                   modification_access),
-                           GlobalRef::Window(global),
+                           global,
                            CSSStyleDeclarationBinding::Wrap)
     }
 
diff --git a/components/script/dom/customevent.rs b/components/script/dom/customevent.rs
index 301c3b6f816..d7e026d69bc 100644
--- a/components/script/dom/customevent.rs
+++ b/components/script/dom/customevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::CustomEventBinding;
 use dom::bindings::codegen::Bindings::CustomEventBinding::CustomEventMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{MutHeapJSVal, Root};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, JSContext};
 use js::jsval::JSVal;
 use string_cache::Atom;
@@ -32,12 +32,12 @@ impl CustomEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<CustomEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<CustomEvent> {
         reflect_dom_object(box CustomEvent::new_inherited(),
                            global,
                            CustomEventBinding::Wrap)
     }
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: bool,
                cancelable: bool,
@@ -47,8 +47,9 @@ impl CustomEvent {
         ev.init_custom_event(type_, bubbles, cancelable, detail);
         ev
     }
+
     #[allow(unsafe_code)]
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &CustomEventBinding::CustomEventInit)
                        -> Fallible<Root<CustomEvent>> {
diff --git a/components/script/dom/dedicatedworkerglobalscope.rs b/components/script/dom/dedicatedworkerglobalscope.rs
index 49a46b88575..fb818be3797 100644
--- a/components/script/dom/dedicatedworkerglobalscope.rs
+++ b/components/script/dom/dedicatedworkerglobalscope.rs
@@ -11,12 +11,12 @@ use dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding;
 use dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding::DedicatedWorkerGlobalScopeMethods;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::error::{ErrorInfo, ErrorResult};
-use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, RootCollection};
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::DOMString;
 use dom::bindings::structuredclone::StructuredCloneData;
+use dom::globalscope::GlobalScope;
 use dom::messageevent::MessageEvent;
 use dom::worker::{TrustedWorkerAddress, WorkerErrorHandler, WorkerMessageHandler};
 use dom::workerglobalscope::WorkerGlobalScope;
@@ -212,7 +212,7 @@ impl DedicatedWorkerGlobalScope {
             }
 
             let reporter_name = format!("dedicated-worker-reporter-{}", random::<u64>());
-            scope.mem_profiler_chan().run_with_memory_reporting(|| {
+            scope.upcast::<GlobalScope>().mem_profiler_chan().run_with_memory_reporting(|| {
                 while let Ok(event) = global.receive_event() {
                     if scope.is_closing() {
                         break;
@@ -281,8 +281,8 @@ impl DedicatedWorkerGlobalScope {
                 let _ac = JSAutoCompartment::new(scope.get_cx(),
                                                  scope.reflector().get_jsobject().get());
                 rooted!(in(scope.get_cx()) let mut message = UndefinedValue());
-                data.read(GlobalRef::Worker(scope), message.handle_mut());
-                MessageEvent::dispatch_jsval(target, GlobalRef::Worker(scope), message.handle());
+                data.read(scope.upcast(), message.handle_mut());
+                MessageEvent::dispatch_jsval(target, scope.upcast(), message.handle());
             },
             WorkerScriptMsg::Common(CommonScriptMsg::RunnableMsg(_, runnable)) => {
                 runnable.handler()
@@ -300,14 +300,13 @@ impl DedicatedWorkerGlobalScope {
     fn handle_event(&self, event: MixedMessage) {
         match event {
             MixedMessage::FromDevtools(msg) => {
-                let global_ref = GlobalRef::Worker(self.upcast());
                 match msg {
                     DevtoolScriptControlMsg::EvaluateJS(_pipe_id, string, sender) =>
-                        devtools::handle_evaluate_js(&global_ref, string, sender),
+                        devtools::handle_evaluate_js(self.upcast(), string, sender),
                     DevtoolScriptControlMsg::GetCachedMessages(pipe_id, message_types, sender) =>
                         devtools::handle_get_cached_messages(pipe_id, message_types, sender),
                     DevtoolScriptControlMsg::WantsLiveNotifications(_pipe_id, bool_val) =>
-                        devtools::handle_wants_live_notifications(&global_ref, bool_val),
+                        devtools::handle_wants_live_notifications(self.upcast(), bool_val),
                     _ => debug!("got an unusable devtools control message inside the worker!"),
                 }
             },
@@ -342,11 +341,9 @@ impl DedicatedWorkerGlobalScope {
 
 #[allow(unsafe_code)]
 unsafe extern "C" fn interrupt_callback(cx: *mut JSContext) -> bool {
-    let global = global_root_from_context(cx);
-    let worker = match global.r() {
-        GlobalRef::Worker(w) => w,
-        _ => panic!("global for worker is not a worker scope")
-    };
+    let worker =
+        Root::downcast::<WorkerGlobalScope>(GlobalScope::from_context(cx))
+            .expect("global is not a worker scope");
     assert!(worker.is::<DedicatedWorkerGlobalScope>());
 
     // A false response causes the script to terminate
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 5e834ef52cd..bf2088bc15c 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -21,7 +21,6 @@ use dom::bindings::codegen::Bindings::TouchBinding::TouchMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::UnionTypes::NodeOrString;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap, Root};
 use dom::bindings::js::RootedReference;
@@ -45,6 +44,7 @@ use dom::eventdispatcher::EventStatus;
 use dom::eventtarget::EventTarget;
 use dom::focusevent::FocusEvent;
 use dom::forcetouchevent::ForceTouchEvent;
+use dom::globalscope::GlobalScope;
 use dom::hashchangeevent::HashChangeEvent;
 use dom::htmlanchorelement::HTMLAnchorElement;
 use dom::htmlappletelement::HTMLAppletElement;
@@ -650,8 +650,9 @@ impl Document {
             // Update the focus state for all elements in the focus chain.
             // https://html.spec.whatwg.org/multipage/#focus-chain
             if focus_type == FocusType::Element {
-                let event = ConstellationMsg::Focus(self.window.pipeline_id());
-                self.window.constellation_chan().send(event).unwrap();
+                let global_scope = self.window.upcast::<GlobalScope>();
+                let event = ConstellationMsg::Focus(global_scope.pipeline_id());
+                global_scope.constellation_chan().send(event).unwrap();
             }
         }
     }
@@ -669,8 +670,10 @@ impl Document {
     /// Sends this document's title to the compositor.
     pub fn send_title_to_compositor(&self) {
         let window = self.window();
-        window.constellation_chan()
-              .send(ConstellationMsg::SetTitle(window.pipeline_id(),
+        let global_scope = window.upcast::<GlobalScope>();
+        global_scope
+              .constellation_chan()
+              .send(ConstellationMsg::SetTitle(global_scope.pipeline_id(),
                                                Some(String::from(self.Title()))))
               .unwrap();
     }
@@ -723,7 +726,7 @@ impl Document {
                 let event = ConstellationMsg::ForwardMouseButtonEvent(pipeline_id,
                                                                       mouse_event_type,
                                                                       button, child_point);
-                self.window.constellation_chan().send(event).unwrap();
+                self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
             }
             return;
         }
@@ -961,7 +964,7 @@ impl Document {
                     let child_point = client_point - child_origin;
 
                     let event = ConstellationMsg::ForwardMouseMoveEvent(pipeline_id, child_point);
-                    self.window.constellation_chan().send(event).unwrap();
+                    self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
                 }
                 return;
             }
@@ -1356,10 +1359,11 @@ impl Document {
     pub fn trigger_mozbrowser_event(&self, event: MozBrowserEvent) {
         if PREFS.is_mozbrowser_enabled() {
             if let Some((parent_pipeline_id, _)) = self.window.parent_info() {
+                let global_scope = self.window.upcast::<GlobalScope>();
                 let event = ConstellationMsg::MozBrowserEvent(parent_pipeline_id,
-                                                              Some(self.window.pipeline_id()),
+                                                              Some(global_scope.pipeline_id()),
                                                               event);
-                self.window.constellation_chan().send(event).unwrap();
+                global_scope.constellation_chan().send(event).unwrap();
             }
         }
     }
@@ -1379,10 +1383,11 @@ impl Document {
         //
         // TODO: Should tick animation only when document is visible
         if !self.running_animation_callbacks.get() {
+            let global_scope = self.window.upcast::<GlobalScope>();
             let event = ConstellationMsg::ChangeRunningAnimationsState(
-                self.window.pipeline_id(),
+                global_scope.pipeline_id(),
                 AnimationState::AnimationCallbacksPresent);
-            self.window.constellation_chan().send(event).unwrap();
+            global_scope.constellation_chan().send(event).unwrap();
         }
 
         ident
@@ -1418,9 +1423,10 @@ impl Document {
         if self.animation_frame_list.borrow().is_empty() {
             mem::swap(&mut *self.animation_frame_list.borrow_mut(),
                       &mut animation_frame_list);
-            let event = ConstellationMsg::ChangeRunningAnimationsState(self.window.pipeline_id(),
+            let global_scope = self.window.upcast::<GlobalScope>();
+            let event = ConstellationMsg::ChangeRunningAnimationsState(global_scope.pipeline_id(),
                                                                        AnimationState::NoAnimationCallbacksPresent);
-            self.window.constellation_chan().send(event).unwrap();
+            global_scope.constellation_chan().send(event).unwrap();
         }
 
         self.running_animation_callbacks.set(false);
@@ -1478,7 +1484,8 @@ impl Document {
         let loader = self.loader.borrow();
         if !loader.is_blocked() && !loader.events_inhibited() {
             let win = self.window();
-            let msg = MainThreadScriptMsg::DocumentLoadsComplete(win.pipeline_id());
+            let msg = MainThreadScriptMsg::DocumentLoadsComplete(
+                win.upcast::<GlobalScope>().pipeline_id());
             win.main_thread_script_chan().send(msg).unwrap();
         }
     }
@@ -1576,9 +1583,10 @@ impl Document {
     }
 
     pub fn notify_constellation_load(&self) {
-        let pipeline_id = self.window.pipeline_id();
+        let global_scope = self.window.upcast::<GlobalScope>();
+        let pipeline_id = global_scope.pipeline_id();
         let load_event = ConstellationMsg::LoadComplete(pipeline_id);
-        self.window.constellation_chan().send(load_event).unwrap();
+        global_scope.constellation_chan().send(load_event).unwrap();
     }
 
     pub fn set_current_parser(&self, script: Option<ParserRef>) {
@@ -1810,7 +1818,7 @@ impl Document {
     }
 
     // https://dom.spec.whatwg.org/#dom-document
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<Document>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<Document>> {
         let win = global.as_window();
         let doc = win.Document();
         let doc = doc.r();
@@ -1848,7 +1856,7 @@ impl Document {
                                                                       doc_loader,
                                                                       referrer,
                                                                       referrer_policy),
-                                          GlobalRef::Window(window),
+                                          window,
                                           DocumentBinding::Wrap);
         {
             let node = document.upcast::<Node>();
@@ -2325,13 +2333,13 @@ impl DocumentMethods for Document {
             "mouseevents" | "mouseevent" =>
                 Ok(Root::upcast(MouseEvent::new_uninitialized(&self.window))),
             "customevent" =>
-                Ok(Root::upcast(CustomEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(CustomEvent::new_uninitialized(self.window.upcast()))),
             "htmlevents" | "events" | "event" | "svgevents" =>
-                Ok(Event::new_uninitialized(GlobalRef::Window(&self.window))),
+                Ok(Event::new_uninitialized(&self.window.upcast())),
             "keyboardevent" =>
                 Ok(Root::upcast(KeyboardEvent::new_uninitialized(&self.window))),
             "messageevent" =>
-                Ok(Root::upcast(MessageEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(MessageEvent::new_uninitialized(self.window.upcast()))),
             "touchevent" =>
                 Ok(Root::upcast(
                     TouchEvent::new_uninitialized(&self.window,
@@ -2341,25 +2349,25 @@ impl DocumentMethods for Document {
                     )
                 )),
             "webglcontextevent" =>
-                Ok(Root::upcast(WebGLContextEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(WebGLContextEvent::new_uninitialized(self.window.upcast()))),
             "storageevent" => {
                 let USVString(url) = self.URL();
                 Ok(Root::upcast(StorageEvent::new_uninitialized(&self.window, DOMString::from(url))))
             },
             "progressevent" =>
-                Ok(Root::upcast(ProgressEvent::new_uninitialized(&self.window))),
+                Ok(Root::upcast(ProgressEvent::new_uninitialized(self.window.upcast()))),
             "focusevent" =>
-                Ok(Root::upcast(FocusEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(FocusEvent::new_uninitialized(self.window.upcast()))),
             "errorevent" =>
-                Ok(Root::upcast(ErrorEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(ErrorEvent::new_uninitialized(self.window.upcast()))),
             "closeevent" =>
-                Ok(Root::upcast(CloseEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(CloseEvent::new_uninitialized(self.window.upcast()))),
             "popstateevent" =>
-                Ok(Root::upcast(PopStateEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(PopStateEvent::new_uninitialized(self.window.upcast()))),
             "hashchangeevent" =>
-                Ok(Root::upcast(HashChangeEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(HashChangeEvent::new_uninitialized(&self.window.upcast()))),
             "pagetransitionevent" =>
-                Ok(Root::upcast(PageTransitionEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+                Ok(Root::upcast(PageTransitionEvent::new_uninitialized(self.window.upcast()))),
             _ =>
                 Err(Error::NotSupported),
         }
@@ -2719,7 +2727,10 @@ impl DocumentMethods for Document {
 
         let url = self.url();
         let (tx, rx) = ipc::channel().unwrap();
-        let _ = self.window.resource_threads().send(GetCookiesForUrl((*url).clone(), tx, NonHTTP));
+        let _ = self.window
+            .upcast::<GlobalScope>()
+            .resource_threads()
+            .send(GetCookiesForUrl((*url).clone(), tx, NonHTTP));
         let cookies = rx.recv().unwrap();
         Ok(cookies.map_or(DOMString::new(), DOMString::from))
     }
@@ -2736,6 +2747,7 @@ impl DocumentMethods for Document {
 
         let url = self.url();
         let _ = self.window
+                    .upcast::<GlobalScope>()
                     .resource_threads()
                     .send(SetCookiesForUrl((*url).clone(), String::from(cookie), NonHTTP));
         Ok(())
@@ -2993,7 +3005,7 @@ impl DocumentProgressHandler {
     fn dispatch_load(&self) {
         let document = self.addr.root();
         let window = document.window();
-        let event = Event::new(GlobalRef::Window(window),
+        let event = Event::new(window.upcast(),
                                atom!("load"),
                                EventBubbles::DoesNotBubble,
                                EventCancelable::NotCancelable);
diff --git a/components/script/dom/documentfragment.rs b/components/script/dom/documentfragment.rs
index 0fba19d5aff..e71ce0f2d26 100644
--- a/components/script/dom/documentfragment.rs
+++ b/components/script/dom/documentfragment.rs
@@ -7,12 +7,12 @@ use dom::bindings::codegen::Bindings::DocumentFragmentBinding::DocumentFragmentM
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::UnionTypes::NodeOrString;
 use dom::bindings::error::{ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::str::DOMString;
 use dom::document::Document;
 use dom::element::Element;
+use dom::globalscope::GlobalScope;
 use dom::htmlcollection::HTMLCollection;
 use dom::node::{Node, window_from_node};
 use dom::nodelist::NodeList;
@@ -38,7 +38,7 @@ impl DocumentFragment {
                            DocumentFragmentBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<DocumentFragment>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<DocumentFragment>> {
         let document = global.as_window().Document();
 
         Ok(DocumentFragment::new(document.r()))
diff --git a/components/script/dom/domexception.rs b/components/script/dom/domexception.rs
index e32d5dc40ac..2a5946193b6 100644
--- a/components/script/dom/domexception.rs
+++ b/components/script/dom/domexception.rs
@@ -5,10 +5,10 @@
 use dom::bindings::codegen::Bindings::DOMExceptionBinding;
 use dom::bindings::codegen::Bindings::DOMExceptionBinding::DOMExceptionConstants;
 use dom::bindings::codegen::Bindings::DOMExceptionBinding::DOMExceptionMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 #[repr(u16)]
 #[derive(JSTraceable, Copy, Clone, Debug, HeapSizeOf)]
@@ -52,7 +52,7 @@ impl DOMException {
         }
     }
 
-    pub fn new(global: GlobalRef, code: DOMErrorName) -> Root<DOMException> {
+    pub fn new(global: &GlobalScope, code: DOMErrorName) -> Root<DOMException> {
         reflect_dom_object(box DOMException::new_inherited(code),
                            global,
                            DOMExceptionBinding::Wrap)
diff --git a/components/script/dom/domimplementation.rs b/components/script/dom/domimplementation.rs
index dd55630204c..42d744bd6a5 100644
--- a/components/script/dom/domimplementation.rs
+++ b/components/script/dom/domimplementation.rs
@@ -8,7 +8,6 @@ use dom::bindings::codegen::Bindings::DOMImplementationBinding::DOMImplementatio
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -43,7 +42,7 @@ impl DOMImplementation {
     pub fn new(document: &Document) -> Root<DOMImplementation> {
         let window = document.window();
         reflect_dom_object(box DOMImplementation::new_inherited(document),
-                           GlobalRef::Window(window),
+                           window,
                            DOMImplementationBinding::Wrap)
     }
 }
diff --git a/components/script/dom/dommatrix.rs b/components/script/dom/dommatrix.rs
index c63290c9326..dbe7a27516c 100644
--- a/components/script/dom/dommatrix.rs
+++ b/components/script/dom/dommatrix.rs
@@ -5,11 +5,11 @@
 use dom::bindings::codegen::Bindings::DOMMatrixBinding::{Wrap, DOMMatrixMethods, DOMMatrixInit};
 use dom::bindings::codegen::Bindings::DOMMatrixReadOnlyBinding::DOMMatrixReadOnlyMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::dommatrixreadonly::{dommatrixinit_to_matrix, DOMMatrixReadOnly, entries_to_matrix};
+use dom::globalscope::GlobalScope;
 use euclid::Matrix4D;
 
 
@@ -20,7 +20,7 @@ pub struct DOMMatrix {
 
 impl DOMMatrix {
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef, is2D: bool, matrix: Matrix4D<f64>) -> Root<Self> {
+    pub fn new(global: &GlobalScope, is2D: bool, matrix: Matrix4D<f64>) -> Root<Self> {
         let dommatrix = Self::new_inherited(is2D, matrix);
         reflect_dom_object(box dommatrix, global, Wrap)
     }
@@ -32,12 +32,12 @@ impl DOMMatrix {
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrix-dommatrix
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<Self>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<Self>> {
         Self::Constructor_(global, vec![1.0, 0.0, 0.0, 1.0, 0.0, 0.0])
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrix-dommatrix-numbersequence
-    pub fn Constructor_(global: GlobalRef, entries: Vec<f64>) -> Fallible<Root<Self>> {
+    pub fn Constructor_(global: &GlobalScope, entries: Vec<f64>) -> Fallible<Root<Self>> {
         entries_to_matrix(&entries[..])
             .map(|(is2D, matrix)| {
                 Self::new(global, is2D, matrix)
@@ -45,14 +45,14 @@ impl DOMMatrix {
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrix-frommatrix
-    pub fn FromMatrix(global: GlobalRef, other: &DOMMatrixInit) -> Fallible<Root<Self>> {
+    pub fn FromMatrix(global: &GlobalScope, other: &DOMMatrixInit) -> Fallible<Root<Self>> {
         dommatrixinit_to_matrix(&other)
             .map(|(is2D, matrix)| {
                 Self::new(global, is2D, matrix)
             })
     }
 
-    pub fn from_readonly(global: GlobalRef, ro: &DOMMatrixReadOnly) -> Root<Self> {
+    pub fn from_readonly(global: &GlobalScope, ro: &DOMMatrixReadOnly) -> Root<Self> {
         Self::new(global, ro.is_2d(), ro.matrix().clone())
     }
 }
diff --git a/components/script/dom/dommatrixreadonly.rs b/components/script/dom/dommatrixreadonly.rs
index 5c6d66c9a1a..fa7c819a1ba 100644
--- a/components/script/dom/dommatrixreadonly.rs
+++ b/components/script/dom/dommatrixreadonly.rs
@@ -8,11 +8,11 @@ use dom::bindings::codegen::Bindings::DOMMatrixReadOnlyBinding::{DOMMatrixReadOn
 use dom::bindings::codegen::Bindings::DOMPointBinding::DOMPointInit;
 use dom::bindings::error;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{reflect_dom_object, Reflectable, Reflector};
 use dom::dommatrix::DOMMatrix;
 use dom::dompoint::DOMPoint;
+use dom::globalscope::GlobalScope;
 use euclid::{Matrix4D, Point4D, Radians};
 use std::cell::{Cell, Ref};
 use std::f64;
@@ -26,7 +26,7 @@ pub struct DOMMatrixReadOnly {
 
 impl DOMMatrixReadOnly {
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef, is2D: bool, matrix: Matrix4D<f64>) -> Root<Self> {
+    pub fn new(global: &GlobalScope, is2D: bool, matrix: Matrix4D<f64>) -> Root<Self> {
         let dommatrix = Self::new_inherited(is2D, matrix);
         reflect_dom_object(box dommatrix, global, Wrap)
     }
@@ -40,12 +40,12 @@ impl DOMMatrixReadOnly {
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-dommatrixreadonly
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<Self>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<Self>> {
         Ok(Self::new(global, true, Matrix4D::identity()))
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-dommatrixreadonly-numbersequence
-    pub fn Constructor_(global: GlobalRef, entries: Vec<f64>) -> Fallible<Root<Self>> {
+    pub fn Constructor_(global: &GlobalScope, entries: Vec<f64>) -> Fallible<Root<Self>> {
         entries_to_matrix(&entries[..])
             .map(|(is2D, matrix)| {
                 Self::new(global, is2D, matrix)
@@ -53,7 +53,7 @@ impl DOMMatrixReadOnly {
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-frommatrix
-    pub fn FromMatrix(global: GlobalRef, other: &DOMMatrixInit) -> Fallible<Root<Self>> {
+    pub fn FromMatrix(global: &GlobalScope, other: &DOMMatrixInit) -> Fallible<Root<Self>> {
         dommatrixinit_to_matrix(&other)
             .map(|(is2D, matrix)| {
                 Self::new(global, is2D, matrix)
@@ -463,48 +463,50 @@ impl DOMMatrixReadOnlyMethods for DOMMatrixReadOnly {
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-translate
     fn Translate(&self, tx: f64, ty: f64, tz: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).TranslateSelf(tx, ty, tz)
+        DOMMatrix::from_readonly(&self.global(), self).TranslateSelf(tx, ty, tz)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-scale
     fn Scale(&self, scaleX: f64, scaleY: Option<f64>, scaleZ: f64,
                     originX: f64, originY: f64, originZ: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).ScaleSelf(scaleX, scaleY, scaleZ, originX, originY, originZ)
+        DOMMatrix::from_readonly(&self.global(), self)
+            .ScaleSelf(scaleX, scaleY, scaleZ, originX, originY, originZ)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-scale3d
     fn Scale3d(&self, scale: f64, originX: f64, originY: f64, originZ: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).Scale3dSelf(scale, originX, originY, originZ)
+        DOMMatrix::from_readonly(&self.global(), self)
+            .Scale3dSelf(scale, originX, originY, originZ)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-rotate
     fn Rotate(&self, rotX: f64, rotY: Option<f64>, rotZ: Option<f64>) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).RotateSelf(rotX, rotY, rotZ)
+        DOMMatrix::from_readonly(&self.global(), self).RotateSelf(rotX, rotY, rotZ)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-rotatefromvector
     fn RotateFromVector(&self, x: f64, y: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).RotateFromVectorSelf(x, y)
+        DOMMatrix::from_readonly(&self.global(), self).RotateFromVectorSelf(x, y)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-rotateaxisangle
     fn RotateAxisAngle(&self, x: f64, y: f64, z: f64, angle: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).RotateAxisAngleSelf(x, y, z, angle)
+        DOMMatrix::from_readonly(&self.global(), self).RotateAxisAngleSelf(x, y, z, angle)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-skewx
     fn SkewX(&self, sx: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).SkewXSelf(sx)
+        DOMMatrix::from_readonly(&self.global(), self).SkewXSelf(sx)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-skewy
     fn SkewY(&self, sy: f64) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).SkewYSelf(sy)
+        DOMMatrix::from_readonly(&self.global(), self).SkewYSelf(sy)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-multiply
     fn Multiply(&self, other: &DOMMatrixInit) -> Fallible<Root<DOMMatrix>> {
-        DOMMatrix::from_readonly(self.global().r(), self).MultiplySelf(&other)
+        DOMMatrix::from_readonly(&self.global(), self).MultiplySelf(&other)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-flipx
@@ -515,7 +517,7 @@ impl DOMMatrixReadOnlyMethods for DOMMatrixReadOnly {
                                         0.0, 0.0, 1.0, 0.0,
                                         0.0, 0.0, 0.0, 1.0);
         let matrix = flip.post_mul(&self.matrix.borrow());
-        DOMMatrix::new(self.global().r(), is2D, matrix)
+        DOMMatrix::new(&self.global(), is2D, matrix)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-flipy
@@ -526,19 +528,24 @@ impl DOMMatrixReadOnlyMethods for DOMMatrixReadOnly {
                                        0.0,  0.0, 1.0, 0.0,
                                        0.0,  0.0, 0.0, 1.0);
         let matrix = flip.post_mul(&self.matrix.borrow());
-        DOMMatrix::new(self.global().r(), is2D, matrix)
+        DOMMatrix::new(&self.global(), is2D, matrix)
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-inverse
     fn Inverse(&self) -> Root<DOMMatrix> {
-        DOMMatrix::from_readonly(self.global().r(), self).InvertSelf()
+        DOMMatrix::from_readonly(&self.global(), self).InvertSelf()
     }
 
     // https://drafts.fxtf.org/geometry-1/#dom-dommatrixreadonly-transformpoint
     fn TransformPoint(&self, point: &DOMPointInit) -> Root<DOMPoint> {
         let matrix = self.matrix.borrow();
         let result = matrix.transform_point4d(&Point4D::new(point.x, point.y, point.z, point.w));
-        DOMPoint::new(self.global().r(), result.x as f64, result.y as f64, result.z as f64, result.w as f64)
+        DOMPoint::new(
+            &self.global(),
+            result.x as f64,
+            result.y as f64,
+            result.z as f64,
+            result.w as f64)
     }
 }
 
diff --git a/components/script/dom/domparser.rs b/components/script/dom/domparser.rs
index a52f0b8b82f..e73d9bf1aad 100644
--- a/components/script/dom/domparser.rs
+++ b/components/script/dom/domparser.rs
@@ -12,12 +12,12 @@ use dom::bindings::codegen::Bindings::DOMParserBinding::SupportedType::Text_xml;
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentReadyState;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::document::{Document, IsHTMLDocument};
 use dom::document::DocumentSource;
+use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use parse::html::{ParseContext, parse_html};
 use parse::xml::{self, parse_xml};
@@ -38,11 +38,11 @@ impl DOMParser {
 
     pub fn new(window: &Window) -> Root<DOMParser> {
         reflect_dom_object(box DOMParser::new_inherited(window),
-                           GlobalRef::Window(window),
+                           window,
                            DOMParserBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<DOMParser>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<DOMParser>> {
         Ok(DOMParser::new(global.as_window()))
     }
 }
diff --git a/components/script/dom/dompoint.rs b/components/script/dom/dompoint.rs
index 906a30ea617..2f77f77c2c1 100644
--- a/components/script/dom/dompoint.rs
+++ b/components/script/dom/dompoint.rs
@@ -5,10 +5,10 @@
 use dom::bindings::codegen::Bindings::DOMPointBinding::{DOMPointInit, DOMPointMethods, Wrap};
 use dom::bindings::codegen::Bindings::DOMPointReadOnlyBinding::DOMPointReadOnlyMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::dompointreadonly::{DOMPointReadOnly, DOMPointWriteMethods};
+use dom::globalscope::GlobalScope;
 
 // http://dev.w3.org/fxtf/geometry/Overview.html#dompoint
 #[dom_struct]
@@ -23,11 +23,11 @@ impl DOMPoint {
         }
     }
 
-    pub fn new(global: GlobalRef, x: f64, y: f64, z: f64, w: f64) -> Root<DOMPoint> {
+    pub fn new(global: &GlobalScope, x: f64, y: f64, z: f64, w: f64) -> Root<DOMPoint> {
         reflect_dom_object(box DOMPoint::new_inherited(x, y, z, w), global, Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        x: f64,
                        y: f64,
                        z: f64,
@@ -36,7 +36,7 @@ impl DOMPoint {
         Ok(DOMPoint::new(global, x, y, z, w))
     }
 
-    pub fn new_from_init(global: GlobalRef, p: &DOMPointInit) -> Root<DOMPoint> {
+    pub fn new_from_init(global: &GlobalScope, p: &DOMPointInit) -> Root<DOMPoint> {
         DOMPoint::new(global, p.x, p.y, p.z, p.w)
     }
 }
diff --git a/components/script/dom/dompointreadonly.rs b/components/script/dom/dompointreadonly.rs
index aa7efa76267..9da4e27a984 100644
--- a/components/script/dom/dompointreadonly.rs
+++ b/components/script/dom/dompointreadonly.rs
@@ -4,9 +4,9 @@
 
 use dom::bindings::codegen::Bindings::DOMPointReadOnlyBinding::{DOMPointReadOnlyMethods, Wrap};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use std::cell::Cell;
 
 // http://dev.w3.org/fxtf/geometry/Overview.html#dompointreadonly
@@ -30,13 +30,13 @@ impl DOMPointReadOnly {
         }
     }
 
-    pub fn new(global: GlobalRef, x: f64, y: f64, z: f64, w: f64) -> Root<DOMPointReadOnly> {
+    pub fn new(global: &GlobalScope, x: f64, y: f64, z: f64, w: f64) -> Root<DOMPointReadOnly> {
         reflect_dom_object(box DOMPointReadOnly::new_inherited(x, y, z, w),
                            global,
                            Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        x: f64,
                        y: f64,
                        z: f64,
diff --git a/components/script/dom/domquad.rs b/components/script/dom/domquad.rs
index a9af14d3d69..7d80dc9d8fd 100644
--- a/components/script/dom/domquad.rs
+++ b/components/script/dom/domquad.rs
@@ -6,11 +6,11 @@ use dom::bindings::codegen::Bindings::DOMPointBinding::{DOMPointInit, DOMPointMe
 use dom::bindings::codegen::Bindings::DOMQuadBinding::{DOMQuadInit, DOMQuadMethods, Wrap};
 use dom::bindings::codegen::Bindings::DOMRectReadOnlyBinding::DOMRectInit;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{Root, JS};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::dompoint::DOMPoint;
 use dom::domrect::DOMRect;
+use dom::globalscope::GlobalScope;
 
 // https://drafts.fxtf.org/geometry/#DOMQuad
 #[dom_struct]
@@ -37,7 +37,7 @@ impl DOMQuad {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                p1: &DOMPoint,
                p2: &DOMPoint,
                p3: &DOMPoint,
@@ -47,7 +47,7 @@ impl DOMQuad {
                            Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        p1: &DOMPointInit,
                        p2: &DOMPointInit,
                        p3: &DOMPointInit,
@@ -61,7 +61,7 @@ impl DOMQuad {
     }
 
     // https://drafts.fxtf.org/geometry/#dom-domquad-fromrect
-    pub fn FromRect(global: GlobalRef, other: &DOMRectInit) -> Root<DOMQuad> {
+    pub fn FromRect(global: &GlobalScope, other: &DOMRectInit) -> Root<DOMQuad> {
         DOMQuad::new(global,
                      &*DOMPoint::new(global, other.x, other.y, 0f64, 1f64),
                      &*DOMPoint::new(global, other.x + other.width, other.y, 0f64, 1f64),
@@ -70,7 +70,7 @@ impl DOMQuad {
     }
 
     // https://drafts.fxtf.org/geometry/#dom-domquad-fromquad
-    pub fn FromQuad(global: GlobalRef, other: &DOMQuadInit) -> Root<DOMQuad> {
+    pub fn FromQuad(global: &GlobalScope, other: &DOMQuadInit) -> Root<DOMQuad> {
         DOMQuad::new(global,
                      &DOMPoint::new_from_init(global, &other.p1),
                      &DOMPoint::new_from_init(global, &other.p2),
@@ -107,7 +107,7 @@ impl DOMQuadMethods for DOMQuad {
         let right = self.p1.X().max(self.p2.X()).max(self.p3.X()).max(self.p4.X());
         let bottom = self.p1.Y().max(self.p2.Y()).max(self.p3.Y()).max(self.p4.Y());
 
-        DOMRect::new(self.global().r(),
+        DOMRect::new(&self.global(),
                      left,
                      top,
                      right - left,
diff --git a/components/script/dom/domrect.rs b/components/script/dom/domrect.rs
index 086e21882c6..78e1b2db22e 100644
--- a/components/script/dom/domrect.rs
+++ b/components/script/dom/domrect.rs
@@ -6,10 +6,10 @@ use dom::bindings::codegen::Bindings::DOMRectBinding;
 use dom::bindings::codegen::Bindings::DOMRectBinding::DOMRectMethods;
 use dom::bindings::codegen::Bindings::DOMRectReadOnlyBinding::DOMRectReadOnlyMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::domrectreadonly::DOMRectReadOnly;
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct DOMRect {
@@ -23,13 +23,13 @@ impl DOMRect {
         }
     }
 
-    pub fn new(global: GlobalRef, x: f64, y: f64, width: f64, height: f64) -> Root<DOMRect> {
+    pub fn new(global: &GlobalScope, x: f64, y: f64, width: f64, height: f64) -> Root<DOMRect> {
         reflect_dom_object(box DOMRect::new_inherited(x, y, width, height),
                            global,
                            DOMRectBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        x: f64,
                        y: f64,
                        width: f64,
diff --git a/components/script/dom/domrectlist.rs b/components/script/dom/domrectlist.rs
index 86774a49ff3..392aa18997e 100644
--- a/components/script/dom/domrectlist.rs
+++ b/components/script/dom/domrectlist.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::DOMRectListBinding;
 use dom::bindings::codegen::Bindings::DOMRectListBinding::DOMRectListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::domrect::DOMRect;
@@ -30,7 +29,7 @@ impl DOMRectList {
         where T: Iterator<Item = Root<DOMRect>>
     {
         reflect_dom_object(box DOMRectList::new_inherited(rects),
-                           GlobalRef::Window(window),
+                           window,
                            DOMRectListBinding::Wrap)
     }
 }
diff --git a/components/script/dom/domrectreadonly.rs b/components/script/dom/domrectreadonly.rs
index 8e72dae6942..ef0c7ce2c67 100644
--- a/components/script/dom/domrectreadonly.rs
+++ b/components/script/dom/domrectreadonly.rs
@@ -4,9 +4,9 @@
 
 use dom::bindings::codegen::Bindings::DOMRectReadOnlyBinding::{DOMRectReadOnlyMethods, Wrap};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use std::cell::Cell;
 
 #[dom_struct]
@@ -29,7 +29,7 @@ impl DOMRectReadOnly {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                x: f64,
                y: f64,
                width: f64,
@@ -40,7 +40,7 @@ impl DOMRectReadOnly {
                            Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        x: f64,
                        y: f64,
                        width: f64,
diff --git a/components/script/dom/domstringmap.rs b/components/script/dom/domstringmap.rs
index 11479d6b5df..687c10ec898 100644
--- a/components/script/dom/domstringmap.rs
+++ b/components/script/dom/domstringmap.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::DOMStringMapBinding;
 use dom::bindings::codegen::Bindings::DOMStringMapBinding::DOMStringMapMethods;
 use dom::bindings::error::ErrorResult;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -29,7 +28,7 @@ impl DOMStringMap {
     pub fn new(element: &HTMLElement) -> Root<DOMStringMap> {
         let window = window_from_node(element);
         reflect_dom_object(box DOMStringMap::new_inherited(element),
-                           GlobalRef::Window(window.r()),
+                           window.r(),
                            DOMStringMapBinding::Wrap)
     }
 }
diff --git a/components/script/dom/domtokenlist.rs b/components/script/dom/domtokenlist.rs
index c1c09de94c2..00f6ba1abb1 100644
--- a/components/script/dom/domtokenlist.rs
+++ b/components/script/dom/domtokenlist.rs
@@ -6,7 +6,6 @@ use dom::attr::Attr;
 use dom::bindings::codegen::Bindings::DOMTokenListBinding;
 use dom::bindings::codegen::Bindings::DOMTokenListBinding::DOMTokenListMethods;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -34,7 +33,7 @@ impl DOMTokenList {
     pub fn new(element: &Element, local_name: &Atom) -> Root<DOMTokenList> {
         let window = window_from_node(element);
         reflect_dom_object(box DOMTokenList::new_inherited(element, local_name.clone()),
-                           GlobalRef::Window(window.r()),
+                           window.r(),
                            DOMTokenListBinding::Wrap)
     }
 
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 5e00cb71c75..13937bf904c 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -21,7 +21,6 @@ use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, ScrollToOp
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::UnionTypes::NodeOrString;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap};
 use dom::bindings::js::{Root, RootedReference};
@@ -1589,7 +1588,7 @@ impl ElementMethods for Element {
         let win = window_from_node(self);
         let raw_rects = self.upcast::<Node>().content_boxes();
         let rects = raw_rects.iter().map(|rect| {
-            DOMRect::new(GlobalRef::Window(win.r()),
+            DOMRect::new(win.upcast(),
                          rect.origin.x.to_f64_px(),
                          rect.origin.y.to_f64_px(),
                          rect.size.width.to_f64_px(),
@@ -1602,7 +1601,7 @@ impl ElementMethods for Element {
     fn GetBoundingClientRect(&self) -> Root<DOMRect> {
         let win = window_from_node(self);
         let rect = self.upcast::<Node>().bounding_content_box();
-        DOMRect::new(GlobalRef::Window(win.r()),
+        DOMRect::new(win.upcast(),
                      rect.origin.x.to_f64_px(),
                      rect.origin.y.to_f64_px(),
                      rect.size.width.to_f64_px(),
diff --git a/components/script/dom/errorevent.rs b/components/script/dom/errorevent.rs
index 61db675f551..edf1118b58c 100644
--- a/components/script/dom/errorevent.rs
+++ b/components/script/dom/errorevent.rs
@@ -7,12 +7,12 @@ use dom::bindings::codegen::Bindings::ErrorEventBinding;
 use dom::bindings::codegen::Bindings::ErrorEventBinding::ErrorEventMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{MutHeapJSVal, Root};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, JSContext};
 use js::jsval::JSVal;
 use std::cell::Cell;
@@ -41,13 +41,13 @@ impl ErrorEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<ErrorEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<ErrorEvent> {
         reflect_dom_object(box ErrorEvent::new_inherited(),
                            global,
                            ErrorEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable,
@@ -70,7 +70,7 @@ impl ErrorEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &ErrorEventBinding::ErrorEventInit) -> Fallible<Root<ErrorEvent>>{
         let msg = match init.message.as_ref() {
@@ -94,11 +94,16 @@ impl ErrorEvent {
         // Dictionaries need to be rooted
         // https://github.com/servo/servo/issues/6381
         rooted!(in(global.get_cx()) let error = init.error);
-        let event = ErrorEvent::new(global, Atom::from(type_),
-                                bubbles, cancelable,
-                                msg, file_name,
-                                line_num, col_num,
-                                error.handle());
+        let event = ErrorEvent::new(
+                global,
+                Atom::from(type_),
+                bubbles,
+                cancelable,
+                msg,
+                file_name,
+                line_num,
+                col_num,
+                error.handle());
         Ok(event)
     }
 
diff --git a/components/script/dom/event.rs b/components/script/dom/event.rs
index a6dfe7c9ac4..cdbfdafec2e 100644
--- a/components/script/dom/event.rs
+++ b/components/script/dom/event.rs
@@ -6,13 +6,13 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::EventBinding;
 use dom::bindings::codegen::Bindings::EventBinding::{EventConstants, EventMethods};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::eventdispatcher::EventStatus;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use script_thread::Runnable;
 use std::cell::Cell;
 use std::default::Default;
@@ -115,13 +115,13 @@ impl Event {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<Event> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<Event> {
         reflect_dom_object(box Event::new_inherited(),
                            global,
                            EventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable) -> Root<Event> {
@@ -130,7 +130,7 @@ impl Event {
         event
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &EventBinding::EventInit) -> Fallible<Root<Event>> {
         let bubbles = EventBubbles::from(init.bubbles);
diff --git a/components/script/dom/eventdispatcher.rs b/components/script/dom/eventdispatcher.rs
index 28ea0b42b31..cb7107e92e5 100644
--- a/components/script/dom/eventdispatcher.rs
+++ b/components/script/dom/eventdispatcher.rs
@@ -5,7 +5,6 @@
 use devtools_traits::{StartedTimelineMarker, TimelineMarker, TimelineMarkerType};
 use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
-use dom::bindings::global::GlobalRoot;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root, RootedReference};
 use dom::bindings::reflector::Reflectable;
@@ -52,8 +51,8 @@ fn dispatch_to_listeners(event: &Event, target: &EventTarget, event_path: &[&Eve
     assert!(!event.stop_propagation());
     assert!(!event.stop_immediate());
 
-    let window = match target.global() {
-        GlobalRoot::Window(window) => {
+    let window = match Root::downcast::<Window>(target.global()) {
+        Some(window) => {
             if window.need_emit_timeline_marker(TimelineMarkerType::DOMEvent) {
                 Some(window)
             } else {
diff --git a/components/script/dom/eventsource.rs b/components/script/dom/eventsource.rs
index 4007e391852..f05e73beafa 100644
--- a/components/script/dom/eventsource.rs
+++ b/components/script/dom/eventsource.rs
@@ -6,11 +6,11 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::EventSourceBinding::{EventSourceInit, EventSourceMethods, Wrap};
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use std::cell::Cell;
 use url::Url;
 
@@ -42,11 +42,13 @@ impl EventSource {
         }
     }
 
-    fn new(global: GlobalRef, url: Url, with_credentials: bool) -> Root<EventSource> {
-        reflect_dom_object(box EventSource::new_inherited(url, with_credentials), global, Wrap)
+    fn new(global: &GlobalScope, url: Url, with_credentials: bool) -> Root<EventSource> {
+        reflect_dom_object(box EventSource::new_inherited(url, with_credentials),
+                           global,
+                           Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        url_str: DOMString,
                        event_source_init: &EventSourceInit) -> Fallible<Root<EventSource>> {
         // Steps 1-2
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index 9bdaac20288..6d6ea81c7b6 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -154,8 +154,7 @@ impl CompiledEventListener {
                 match *handler {
                     CommonEventHandler::ErrorEventHandler(ref handler) => {
                         if let Some(event) = event.downcast::<ErrorEvent>() {
-                            let global = object.global();
-                            let cx = global.r().get_cx();
+                            let cx = object.global().get_cx();
                             rooted!(in(cx) let error = event.Error(cx));
                             let return_value = handler.Call_(object,
                                                              EventOrString::String(event.Message()),
@@ -201,8 +200,7 @@ impl CompiledEventListener {
 
                     CommonEventHandler::EventHandler(ref handler) => {
                         if let Ok(value) = handler.Call_(object, event, exception_handle) {
-                            let global = object.global();
-                            let cx = global.r().get_cx();
+                            let cx = object.global().get_cx();
                             rooted!(in(cx) let value = value);
                             let value = value.handle();
 
@@ -500,8 +498,7 @@ impl EventTarget {
                       bubbles: EventBubbles,
                       cancelable: EventCancelable)
                       -> Root<Event> {
-        let global = self.global();
-        let event = Event::new(global.r(), Atom::from(name), bubbles, cancelable);
+        let event = Event::new(&self.global(), Atom::from(name), bubbles, cancelable);
 
         event.fire(self);
 
diff --git a/components/script/dom/extendableevent.rs b/components/script/dom/extendableevent.rs
index ffb6c3baad2..d859d8f4724 100644
--- a/components/script/dom/extendableevent.rs
+++ b/components/script/dom/extendableevent.rs
@@ -5,12 +5,12 @@
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::ExtendableEventBinding;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, JSContext};
 use string_cache::Atom;
 
@@ -28,7 +28,7 @@ impl ExtendableEvent {
             extensions_allowed: true
         }
     }
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: bool,
                cancelable: bool)
@@ -41,7 +41,7 @@ impl ExtendableEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &ExtendableEventBinding::ExtendableEventInit) -> Fallible<Root<ExtendableEvent>> {
         Ok(ExtendableEvent::new(global,
diff --git a/components/script/dom/extendablemessageevent.rs b/components/script/dom/extendablemessageevent.rs
index 202c81c0416..0a5968d1d99 100644
--- a/components/script/dom/extendablemessageevent.rs
+++ b/components/script/dom/extendablemessageevent.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::ExtendableMessageEventBinding;
 use dom::bindings::codegen::Bindings::ExtendableMessageEventBinding::ExtendableMessageEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
@@ -13,6 +12,7 @@ use dom::bindings::str::DOMString;
 use dom::event::Event;
 use dom::eventtarget::EventTarget;
 use dom::extendableevent::ExtendableEvent;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, Heap, JSContext};
 use js::jsval::JSVal;
 use std::default::Default;
@@ -27,7 +27,7 @@ pub struct ExtendableMessageEvent {
 }
 
 impl ExtendableMessageEvent {
-    pub fn new(global: GlobalRef, type_: Atom,
+    pub fn new(global: &GlobalScope, type_: Atom,
                bubbles: bool, cancelable: bool,
                data: HandleValue, origin: DOMString, lastEventId: DOMString)
                -> Root<ExtendableMessageEvent> {
@@ -46,12 +46,13 @@ impl ExtendableMessageEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &ExtendableMessageEventBinding::ExtendableMessageEventInit)
                        -> Fallible<Root<ExtendableMessageEvent>> {
         rooted!(in(global.get_cx()) let data = init.data);
-        let ev = ExtendableMessageEvent::new(global, Atom::from(type_),
+        let ev = ExtendableMessageEvent::new(global,
+                                             Atom::from(type_),
                                              init.parent.parent.bubbles,
                                              init.parent.parent.cancelable,
                                              data.handle(),
@@ -63,7 +64,7 @@ impl ExtendableMessageEvent {
 
 impl ExtendableMessageEvent {
     pub fn dispatch_jsval(target: &EventTarget,
-                          scope: GlobalRef,
+                          scope: &GlobalScope,
                           message: HandleValue) {
         let Extendablemessageevent = ExtendableMessageEvent::new(
             scope, atom!("message"), false, false, message,
diff --git a/components/script/dom/file.rs b/components/script/dom/file.rs
index 8b4abaaed80..dba94a85e50 100644
--- a/components/script/dom/file.rs
+++ b/components/script/dom/file.rs
@@ -6,11 +6,12 @@ use dom::bindings::codegen::Bindings::FileBinding;
 use dom::bindings::codegen::Bindings::FileBinding::FileMethods;
 use dom::bindings::codegen::UnionTypes::BlobOrString;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::blob::{Blob, BlobImpl, blob_parts_to_bytes};
+use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use net_traits::filemanager_thread::SelectedFile;
 use time;
@@ -41,7 +42,7 @@ impl File {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef, blob_impl: BlobImpl,
+    pub fn new(global: &GlobalScope, blob_impl: BlobImpl,
                name: DOMString, modified: Option<i64>, typeString: &str) -> Root<File> {
         reflect_dom_object(box File::new_inherited(blob_impl, name, modified, typeString),
                            global,
@@ -52,14 +53,12 @@ impl File {
     pub fn new_from_selected(window: &Window, selected: SelectedFile) -> Root<File> {
         let name = DOMString::from(selected.filename.to_str().expect("File name encoding error"));
 
-        let global = GlobalRef::Window(window);
-
-        File::new(global, BlobImpl::new_from_file(selected.id, selected.filename, selected.size),
+        File::new(window.upcast(), BlobImpl::new_from_file(selected.id, selected.filename, selected.size),
                   name, Some(selected.modified as i64), &selected.type_string)
     }
 
     // https://w3c.github.io/FileAPI/#file-constructor
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        fileBits: Vec<BlobOrString>,
                        filename: DOMString,
                        filePropertyBag: &FileBinding::FilePropertyBag)
@@ -76,7 +75,11 @@ impl File {
         // NOTE: Following behaviour might be removed in future,
         // see https://github.com/w3c/FileAPI/issues/41
         let replaced_filename = DOMString::from_string(filename.replace("/", ":"));
-        Ok(File::new(global, BlobImpl::new_from_bytes(bytes), replaced_filename, modified, typeString))
+        Ok(File::new(global,
+                     BlobImpl::new_from_bytes(bytes),
+                     replaced_filename,
+                     modified,
+                     typeString))
     }
 
     pub fn name(&self) -> &DOMString {
diff --git a/components/script/dom/filelist.rs b/components/script/dom/filelist.rs
index 8adbe1ed467..e3654b752dc 100644
--- a/components/script/dom/filelist.rs
+++ b/components/script/dom/filelist.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::FileListBinding;
 use dom::bindings::codegen::Bindings::FileListBinding::FileListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::file::File;
@@ -30,7 +29,7 @@ impl FileList {
     #[allow(unrooted_must_root)]
     pub fn new(window: &Window, files: Vec<Root<File>>) -> Root<FileList> {
         reflect_dom_object(box FileList::new_inherited(files.iter().map(|r| JS::from_ref(&**r)).collect()),
-                           GlobalRef::Window(window),
+                           window,
                            FileListBinding::Wrap)
     }
 
diff --git a/components/script/dom/filereader.rs b/components/script/dom/filereader.rs
index a82e4dc47bc..296a6461b55 100644
--- a/components/script/dom/filereader.rs
+++ b/components/script/dom/filereader.rs
@@ -7,7 +7,6 @@ use dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::FileReaderBinding::{self, FileReaderConstants, FileReaderMethods};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::refcounted::Trusted;
@@ -17,6 +16,7 @@ use dom::blob::Blob;
 use dom::domexception::{DOMErrorName, DOMException};
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::progressevent::ProgressEvent;
 use encoding::all::UTF_8;
 use encoding::label::encoding_from_whatwg_label;
@@ -88,12 +88,12 @@ impl FileReader {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<FileReader> {
+    pub fn new(global: &GlobalScope) -> Root<FileReader> {
         reflect_dom_object(box FileReader::new_inherited(),
                            global, FileReaderBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<FileReader>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<FileReader>> {
         Ok(FileReader::new(global))
     }
 
@@ -114,8 +114,7 @@ impl FileReader {
         fr.change_ready_state(FileReaderReadyState::Done);
         *fr.result.borrow_mut() = None;
 
-        let global = fr.r().global();
-        let exception = DOMException::new(global.r(), error);
+        let exception = DOMException::new(&fr.global(), error);
         fr.error.set(Some(&exception));
 
         fr.dispatch_progress_event(atom!("error"), 0, None);
@@ -289,8 +288,7 @@ impl FileReaderMethods for FileReader {
         // Steps 1 & 3
         *self.result.borrow_mut() = None;
 
-        let global = self.global();
-        let exception = DOMException::new(global.r(), DOMErrorName::AbortError);
+        let exception = DOMException::new(&self.global(), DOMErrorName::AbortError);
         self.error.set(Some(&exception));
 
         self.terminate_ongoing_reading();
@@ -318,8 +316,7 @@ impl FileReaderMethods for FileReader {
 
 impl FileReader {
     fn dispatch_progress_event(&self, type_: Atom, loaded: u64, total: Option<u64>) {
-        let global = self.global();
-        let progressevent = ProgressEvent::new(global.r(),
+        let progressevent = ProgressEvent::new(&self.global(),
             type_, EventBubbles::DoesNotBubble, EventCancelable::NotCancelable,
             total.is_some(), loaded, total.unwrap_or(0));
         progressevent.upcast::<Event>().fire(self.upcast());
@@ -336,9 +333,9 @@ impl FileReader {
             return Err(Error::InvalidState);
         }
         // Step 2
+        let global = self.global();
         if blob.IsClosed() {
-            let global = self.global();
-            let exception = DOMException::new(global.r(), DOMErrorName::InvalidStateError);
+            let exception = DOMException::new(&global, DOMErrorName::InvalidStateError);
             self.error.set(Some(&exception));
 
             self.dispatch_progress_event(atom!("error"), 0, None);
@@ -358,8 +355,9 @@ impl FileReader {
         let fr = Trusted::new(self);
         let gen_id = self.generation_id.get();
 
-        let wrapper = self.global().r().get_runnable_wrapper();
-        let task_source = self.global().r().file_reading_task_source();
+        let global = self.global();
+        let wrapper = global.get_runnable_wrapper();
+        let task_source = global.file_reading_task_source();
 
         spawn_named("file reader async operation".to_owned(), move || {
             perform_annotated_read_operation(gen_id, load_data, blob_contents, fr, task_source, wrapper)
diff --git a/components/script/dom/filereadersync.rs b/components/script/dom/filereadersync.rs
index b248848edad..875843ea0c6 100644
--- a/components/script/dom/filereadersync.rs
+++ b/components/script/dom/filereadersync.rs
@@ -4,12 +4,10 @@
 
 use dom::bindings::codegen::Bindings::FileReaderSyncBinding;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::eventtarget::EventTarget;
-
-
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct FileReaderSync {
@@ -23,12 +21,12 @@ impl FileReaderSync {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<FileReaderSync> {
+    pub fn new(global: &GlobalScope) -> Root<FileReaderSync> {
         reflect_dom_object(box FileReaderSync::new_inherited(),
                            global, FileReaderSyncBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<FileReaderSync>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<FileReaderSync>> {
         Ok(FileReaderSync::new(global))
     }
 }
diff --git a/components/script/dom/focusevent.rs b/components/script/dom/focusevent.rs
index dd5e41e8426..d06b725286d 100644
--- a/components/script/dom/focusevent.rs
+++ b/components/script/dom/focusevent.rs
@@ -6,13 +6,13 @@ use dom::bindings::codegen::Bindings::FocusEventBinding;
 use dom::bindings::codegen::Bindings::FocusEventBinding::FocusEventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::uievent::UIEvent;
 use dom::window::Window;
 use std::default::Default;
@@ -31,7 +31,7 @@ impl FocusEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<FocusEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<FocusEvent> {
         reflect_dom_object(box FocusEvent::new_inherited(),
                            global,
                            FocusEventBinding::Wrap)
@@ -44,8 +44,7 @@ impl FocusEvent {
                view: Option<&Window>,
                detail: i32,
                related_target: Option<&EventTarget>) -> Root<FocusEvent> {
-        let event = box FocusEvent::new_inherited();
-        let ev = reflect_dom_object(event, GlobalRef::Window(window), FocusEventBinding::Wrap);
+        let ev = FocusEvent::new_uninitialized(window.upcast());
         ev.upcast::<UIEvent>().InitUIEvent(type_,
                                            bool::from(can_bubble),
                                            bool::from(cancelable),
@@ -54,12 +53,13 @@ impl FocusEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &FocusEventBinding::FocusEventInit) -> Fallible<Root<FocusEvent>> {
         let bubbles = EventBubbles::from(init.parent.parent.bubbles);
         let cancelable = EventCancelable::from(init.parent.parent.cancelable);
-        let event = FocusEvent::new(global.as_window(), type_,
+        let event = FocusEvent::new(global.as_window(),
+                                    type_,
                                     bubbles,
                                     cancelable,
                                     init.parent.view.r(),
diff --git a/components/script/dom/forcetouchevent.rs b/components/script/dom/forcetouchevent.rs
index e982cfdf86e..9e1c5cfcd91 100644
--- a/components/script/dom/forcetouchevent.rs
+++ b/components/script/dom/forcetouchevent.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::ForceTouchEventBinding;
 use dom::bindings::codegen::Bindings::ForceTouchEventBinding::ForceTouchEventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::num::Finite;
@@ -32,7 +31,7 @@ impl ForceTouchEvent {
                type_: DOMString,
                force: f32) -> Root<ForceTouchEvent> {
         let event = box ForceTouchEvent::new_inherited(force);
-        let ev = reflect_dom_object(event, GlobalRef::Window(window), ForceTouchEventBinding::Wrap);
+        let ev = reflect_dom_object(event, window, ForceTouchEventBinding::Wrap);
         ev.upcast::<UIEvent>().InitUIEvent(type_, true, true, Some(window), 0);
         ev
     }
diff --git a/components/script/dom/formdata.rs b/components/script/dom/formdata.rs
index 542b44e804e..2c8f99b424b 100644
--- a/components/script/dom/formdata.rs
+++ b/components/script/dom/formdata.rs
@@ -7,13 +7,13 @@ use dom::bindings::codegen::Bindings::FormDataBinding::FormDataMethods;
 use dom::bindings::codegen::Bindings::FormDataBinding::FormDataWrap;
 use dom::bindings::codegen::UnionTypes::FileOrUSVString;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::iterable::Iterable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
 use dom::blob::{Blob, BlobImpl};
 use dom::file::File;
+use dom::globalscope::GlobalScope;
 use dom::htmlformelement::{HTMLFormElement, FormDatumValue, FormDatum};
 use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
@@ -45,12 +45,12 @@ impl FormData {
         }
     }
 
-    pub fn new(form: Option<&HTMLFormElement>, global: GlobalRef) -> Root<FormData> {
+    pub fn new(form: Option<&HTMLFormElement>, global: &GlobalScope) -> Root<FormData> {
         reflect_dom_object(box FormData::new_inherited(form),
                            global, FormDataWrap)
     }
 
-    pub fn Constructor(global: GlobalRef, form: Option<&HTMLFormElement>) -> Fallible<Root<FormData>> {
+    pub fn Constructor(global: &GlobalScope, form: Option<&HTMLFormElement>) -> Fallible<Root<FormData>> {
         // TODO: Construct form data set for form if it is supplied
         Ok(FormData::new(form, global))
     }
@@ -145,8 +145,6 @@ impl FormDataMethods for FormData {
 
 impl FormData {
     fn get_file(&self, blob: &Blob, opt_filename: Option<USVString>) -> Root<File> {
-        let global = self.global();
-
         let name = match opt_filename {
             Some(filename) => DOMString::from(filename.0),
             None => DOMString::from(""),
@@ -154,7 +152,7 @@ impl FormData {
 
         let bytes = blob.get_bytes().unwrap_or(vec![]);
 
-        File::new(global.r(), BlobImpl::new_from_bytes(bytes), name, None, "")
+        File::new(&self.global(), BlobImpl::new_from_bytes(bytes), name, None, "")
     }
 
     pub fn datums(&self) -> Vec<FormDatum> {
diff --git a/components/script/dom/globalscope.rs b/components/script/dom/globalscope.rs
new file mode 100644
index 00000000000..fc160675df5
--- /dev/null
+++ b/components/script/dom/globalscope.rs
@@ -0,0 +1,524 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use devtools_traits::{ScriptToDevtoolsControlMsg, WorkerId};
+use dom::bindings::cell::DOMRefCell;
+use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
+use dom::bindings::conversions::root_from_object;
+use dom::bindings::error::{ErrorInfo, report_pending_exception};
+use dom::bindings::inheritance::Castable;
+use dom::bindings::js::{JS, MutNullableHeap, Root};
+use dom::bindings::reflector::Reflectable;
+use dom::bindings::str::DOMString;
+use dom::crypto::Crypto;
+use dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
+use dom::errorevent::ErrorEvent;
+use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::eventdispatcher::EventStatus;
+use dom::eventtarget::EventTarget;
+use dom::window::Window;
+use dom::workerglobalscope::WorkerGlobalScope;
+use ipc_channel::ipc::IpcSender;
+use js::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
+use js::glue::{IsWrapper, UnwrapObject};
+use js::jsapi::{CurrentGlobalOrNull, GetGlobalForObjectCrossCompartment};
+use js::jsapi::{HandleValue, Evaluate2, JSAutoCompartment, JSContext};
+use js::jsapi::{JSObject, JS_GetClass, JS_GetContext};
+use js::jsapi::{JS_GetObjectRuntime, MutableHandleValue};
+use js::rust::CompileOptionsWrapper;
+use libc;
+use msg::constellation_msg::PipelineId;
+use net_traits::{CoreResourceThread, ResourceThreads, IpcSend};
+use profile_traits::{mem, time};
+use script_runtime::{CommonScriptMsg, EnqueuedPromiseCallback, ScriptChan};
+use script_runtime::{ScriptPort, maybe_take_panic_result};
+use script_thread::{MainThreadScriptChan, RunnableWrapper, ScriptThread};
+use script_traits::{MsDuration, ScriptMsg as ConstellationMsg, TimerEvent};
+use script_traits::{TimerEventId, TimerEventRequest, TimerSource};
+use std::cell::Cell;
+use std::collections::HashMap;
+use std::collections::hash_map::Entry;
+use std::ffi::CString;
+use std::panic;
+use task_source::file_reading::FileReadingTaskSource;
+use time::{Timespec, get_time};
+use timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle};
+use timers::{OneshotTimers, TimerCallback};
+use url::Url;
+
+#[dom_struct]
+pub struct GlobalScope {
+    eventtarget: EventTarget,
+    crypto: MutNullableHeap<JS<Crypto>>,
+    next_worker_id: Cell<WorkerId>,
+
+    /// Pipeline id associated with this global.
+    pipeline_id: PipelineId,
+
+    /// A flag to indicate whether the developer tools has requested
+    /// live updates from the worker.
+    devtools_wants_updates: Cell<bool>,
+
+    /// Timers used by the Console API.
+    console_timers: DOMRefCell<HashMap<DOMString, u64>>,
+
+    /// For providing instructions to an optional devtools server.
+    #[ignore_heap_size_of = "channels are hard"]
+    devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
+
+    /// For sending messages to the memory profiler.
+    #[ignore_heap_size_of = "channels are hard"]
+    mem_profiler_chan: mem::ProfilerChan,
+
+    /// For sending messages to the time profiler.
+    #[ignore_heap_size_of = "channels are hard"]
+    time_profiler_chan: time::ProfilerChan,
+
+    /// A handle for communicating messages to the constellation thread.
+    #[ignore_heap_size_of = "channels are hard"]
+    constellation_chan: IpcSender<ConstellationMsg>,
+
+    #[ignore_heap_size_of = "channels are hard"]
+    scheduler_chan: IpcSender<TimerEventRequest>,
+
+    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
+    in_error_reporting_mode: Cell<bool>,
+
+    /// Associated resource threads for use by DOM objects like XMLHttpRequest,
+    /// including resource_thread, filemanager_thread and storage_thread
+    resource_threads: ResourceThreads,
+
+    timers: OneshotTimers,
+}
+
+impl GlobalScope {
+    pub fn new_inherited(
+            pipeline_id: PipelineId,
+            devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
+            mem_profiler_chan: mem::ProfilerChan,
+            time_profiler_chan: time::ProfilerChan,
+            constellation_chan: IpcSender<ConstellationMsg>,
+            scheduler_chan: IpcSender<TimerEventRequest>,
+            resource_threads: ResourceThreads,
+            timer_event_chan: IpcSender<TimerEvent>)
+            -> Self {
+        GlobalScope {
+            eventtarget: EventTarget::new_inherited(),
+            crypto: Default::default(),
+            next_worker_id: Cell::new(WorkerId(0)),
+            pipeline_id: pipeline_id,
+            devtools_wants_updates: Default::default(),
+            console_timers: DOMRefCell::new(Default::default()),
+            devtools_chan: devtools_chan,
+            mem_profiler_chan: mem_profiler_chan,
+            time_profiler_chan: time_profiler_chan,
+            constellation_chan: constellation_chan,
+            scheduler_chan: scheduler_chan.clone(),
+            in_error_reporting_mode: Default::default(),
+            resource_threads: resource_threads,
+            timers: OneshotTimers::new(timer_event_chan, scheduler_chan),
+        }
+    }
+
+    /// Returns the global scope of the realm that the given DOM object's reflector
+    /// was created in.
+    #[allow(unsafe_code)]
+    pub fn from_reflector<T: Reflectable>(reflector: &T) -> Root<Self> {
+        unsafe { GlobalScope::from_object(*reflector.reflector().get_jsobject()) }
+    }
+
+    /// Returns the global scope of the realm that the given JS object was created in.
+    #[allow(unsafe_code)]
+    pub unsafe fn from_object(obj: *mut JSObject) -> Root<Self> {
+        assert!(!obj.is_null());
+        let global = GetGlobalForObjectCrossCompartment(obj);
+        global_scope_from_global(global)
+    }
+
+    /// Returns the global scope for the given JSContext
+    #[allow(unsafe_code)]
+    pub unsafe fn from_context(cx: *mut JSContext) -> Root<Self> {
+        let global = CurrentGlobalOrNull(cx);
+        global_scope_from_global(global)
+    }
+
+    /// Returns the global object of the realm that the given JS object
+    /// was created in, after unwrapping any wrappers.
+    #[allow(unsafe_code)]
+    pub unsafe fn from_object_maybe_wrapped(mut obj: *mut JSObject) -> Root<Self> {
+        if IsWrapper(obj) {
+            obj = UnwrapObject(obj, /* stopAtWindowProxy = */ 0);
+            assert!(!obj.is_null());
+        }
+        GlobalScope::from_object(obj)
+    }
+
+    #[allow(unsafe_code)]
+    pub fn get_cx(&self) -> *mut JSContext {
+        unsafe {
+            let runtime = JS_GetObjectRuntime(
+                self.reflector().get_jsobject().get());
+            assert!(!runtime.is_null());
+            let context = JS_GetContext(runtime);
+            assert!(!context.is_null());
+            context
+        }
+    }
+
+    pub fn crypto(&self) -> Root<Crypto> {
+        self.crypto.or_init(|| Crypto::new(self))
+    }
+
+    /// Get next worker id.
+    pub fn get_next_worker_id(&self) -> WorkerId {
+        let worker_id = self.next_worker_id.get();
+        let WorkerId(id_num) = worker_id;
+        self.next_worker_id.set(WorkerId(id_num + 1));
+        worker_id
+    }
+
+    pub fn live_devtools_updates(&self) -> bool {
+        self.devtools_wants_updates.get()
+    }
+
+    pub fn set_devtools_wants_updates(&self, value: bool) {
+        self.devtools_wants_updates.set(value);
+    }
+
+    pub fn time(&self, label: DOMString) -> Result<(), ()> {
+        let mut timers = self.console_timers.borrow_mut();
+        if timers.len() >= 10000 {
+            return Err(());
+        }
+        match timers.entry(label) {
+            Entry::Vacant(entry) => {
+                entry.insert(timestamp_in_ms(get_time()));
+                Ok(())
+            },
+            Entry::Occupied(_) => Err(()),
+        }
+    }
+
+    pub fn time_end(&self, label: &str) -> Result<u64, ()> {
+        self.console_timers.borrow_mut().remove(label).ok_or(()).map(|start| {
+            timestamp_in_ms(get_time()) - start
+        })
+    }
+
+    /// Get an `&IpcSender<ScriptToDevtoolsControlMsg>` to send messages
+    /// to the devtools thread when available.
+    pub fn devtools_chan(&self) -> Option<&IpcSender<ScriptToDevtoolsControlMsg>> {
+        self.devtools_chan.as_ref()
+    }
+
+    /// Get a sender to the memory profiler thread.
+    pub fn mem_profiler_chan(&self) -> &mem::ProfilerChan {
+        &self.mem_profiler_chan
+    }
+
+    /// Get a sender to the time profiler thread.
+    pub fn time_profiler_chan(&self) -> &time::ProfilerChan {
+        &self.time_profiler_chan
+    }
+
+    /// Get a sender to the constellation thread.
+    pub fn constellation_chan(&self) -> &IpcSender<ConstellationMsg> {
+        &self.constellation_chan
+    }
+
+    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
+        &self.scheduler_chan
+    }
+
+    /// Get the `PipelineId` for this global scope.
+    pub fn pipeline_id(&self) -> PipelineId {
+        self.pipeline_id
+    }
+
+    /// Get the [base url](https://html.spec.whatwg.org/multipage/#api-base-url)
+    /// for this global scope.
+    pub fn api_base_url(&self) -> Url {
+        if let Some(window) = self.downcast::<Window>() {
+            // https://html.spec.whatwg.org/multipage/#script-settings-for-browsing-contexts:api-base-url
+            return window.Document().base_url();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            // https://html.spec.whatwg.org/multipage/#script-settings-for-workers:api-base-url
+            return worker.get_url().clone();
+        }
+        unreachable!();
+    }
+
+    /// Get the URL for this global scope.
+    pub fn get_url(&self) -> Url {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.get_url();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.get_url().clone();
+        }
+        unreachable!();
+    }
+
+    /// Extract a `Window`, panic if the global object is not a `Window`.
+    pub fn as_window(&self) -> &Window {
+        self.downcast::<Window>().expect("expected a Window scope")
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#report-the-error
+    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
+        // Step 1.
+        if self.in_error_reporting_mode.get() {
+            return;
+        }
+
+        // Step 2.
+        self.in_error_reporting_mode.set(true);
+
+        // Steps 3-12.
+        // FIXME(#13195): muted errors.
+        let event = ErrorEvent::new(self,
+                                    atom!("error"),
+                                    EventBubbles::DoesNotBubble,
+                                    EventCancelable::Cancelable,
+                                    error_info.message.as_str().into(),
+                                    error_info.filename.as_str().into(),
+                                    error_info.lineno,
+                                    error_info.column,
+                                    value);
+
+        // Step 13.
+        let event_status = event.upcast::<Event>().fire(self.upcast::<EventTarget>());
+
+        // Step 15
+        if event_status == EventStatus::NotCanceled {
+            if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
+                dedicated.forward_error_to_worker_object(error_info);
+            }
+        }
+
+        // Step 14
+        self.in_error_reporting_mode.set(false);
+    }
+
+    /// Get the `&ResourceThreads` for this global scope.
+    pub fn resource_threads(&self) -> &ResourceThreads {
+        &self.resource_threads
+    }
+
+    /// Get the `CoreResourceThread` for this global scope.
+    pub fn core_resource_thread(&self) -> CoreResourceThread {
+        self.resource_threads().sender()
+    }
+
+    /// `ScriptChan` to send messages to the event loop of this global scope.
+    pub fn script_chan(&self) -> Box<ScriptChan + Send> {
+        if let Some(window) = self.downcast::<Window>() {
+            return MainThreadScriptChan(window.main_thread_script_chan().clone()).clone();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.script_chan();
+        }
+        unreachable!();
+    }
+
+    /// `ScriptChan` to send messages to the networking task source of
+    /// this of this global scope.
+    pub fn networking_task_source(&self) -> Box<ScriptChan + Send> {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.networking_task_source();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.script_chan();
+        }
+        unreachable!();
+    }
+
+    /// Evaluate JS code on this global scope.
+    pub fn evaluate_js_on_global_with_result(
+            &self, code: &str, rval: MutableHandleValue) {
+        self.evaluate_script_on_global_with_result(code, "", rval)
+    }
+
+    /// Evaluate a JS script on this global scope.
+    #[allow(unsafe_code)]
+    pub fn evaluate_script_on_global_with_result(
+            &self, code: &str, filename: &str, rval: MutableHandleValue) {
+        let metadata = time::TimerMetadata {
+            url: if filename.is_empty() {
+                self.get_url().as_str().into()
+            } else {
+                filename.into()
+            },
+            iframe: time::TimerMetadataFrameType::RootWindow,
+            incremental: time::TimerMetadataReflowType::FirstReflow,
+        };
+        time::profile(
+            time::ProfilerCategory::ScriptEvaluate,
+            Some(metadata),
+            self.time_profiler_chan().clone(),
+            || {
+                let cx = self.get_cx();
+                let globalhandle = self.reflector().get_jsobject();
+                let code: Vec<u16> = code.encode_utf16().collect();
+                let filename = CString::new(filename).unwrap();
+
+                let _ac = JSAutoCompartment::new(cx, globalhandle.get());
+                let options = CompileOptionsWrapper::new(cx, filename.as_ptr(), 1);
+                unsafe {
+                    if !Evaluate2(cx, options.ptr, code.as_ptr(),
+                                  code.len() as libc::size_t,
+                                  rval) {
+                        debug!("error evaluating JS string");
+                        report_pending_exception(cx, true);
+                    }
+                }
+
+                if let Some(error) = maybe_take_panic_result() {
+                    panic::resume_unwind(error);
+                }
+            }
+        )
+    }
+
+    pub fn schedule_callback(
+            &self, callback: OneshotTimerCallback, duration: MsDuration)
+            -> OneshotTimerHandle {
+        self.timers.schedule_callback(callback, duration, self.timer_source())
+    }
+
+    pub fn unschedule_callback(&self, handle: OneshotTimerHandle) {
+        self.timers.unschedule_callback(handle);
+    }
+
+    pub fn set_timeout_or_interval(
+            &self,
+            callback: TimerCallback,
+            arguments: Vec<HandleValue>,
+            timeout: i32,
+            is_interval: IsInterval)
+            -> i32 {
+        self.timers.set_timeout_or_interval(
+            self, callback, arguments, timeout, is_interval, self.timer_source())
+    }
+
+    pub fn clear_timeout_or_interval(&self, handle: i32) {
+        self.timers.clear_timeout_or_interval(self, handle)
+    }
+
+    pub fn fire_timer(&self, handle: TimerEventId) {
+        self.timers.fire_timer(handle, self)
+    }
+
+    pub fn resume(&self) {
+        self.timers.resume()
+    }
+
+    pub fn suspend(&self) {
+        self.timers.suspend()
+    }
+
+    pub fn slow_down_timers(&self) {
+        self.timers.slow_down()
+    }
+
+    pub fn speed_up_timers(&self) {
+        self.timers.speed_up()
+    }
+
+    fn timer_source(&self) -> TimerSource {
+        if self.is::<Window>() {
+            return TimerSource::FromWindow(self.pipeline_id());
+        }
+        if self.is::<WorkerGlobalScope>() {
+            return TimerSource::FromWorker;
+        }
+        unreachable!();
+    }
+
+    /// Returns a wrapper for runnables to ensure they are cancelled if
+    /// the global scope is being destroyed.
+    pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.get_runnable_wrapper();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.get_runnable_wrapper();
+        }
+        unreachable!();
+    }
+
+    /// Start the process of executing the pending promise callbacks. They will be invoked
+    /// in FIFO order, synchronously, at some point in the future.
+    pub fn flush_promise_jobs(&self) {
+        if self.is::<Window>() {
+            return ScriptThread::flush_promise_jobs(self);
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.flush_promise_jobs();
+        }
+        unreachable!();
+    }
+
+    /// Enqueue a promise callback for subsequent execution.
+    pub fn enqueue_promise_job(&self, job: EnqueuedPromiseCallback) {
+        if self.is::<Window>() {
+            return ScriptThread::enqueue_promise_job(job, self);
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.enqueue_promise_job(job);
+        }
+        unreachable!();
+    }
+
+    /// Create a new sender/receiver pair that can be used to implement an on-demand
+    /// event loop. Used for implementing web APIs that require blocking semantics
+    /// without resorting to nested event loops.
+    pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.new_script_pair();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.new_script_pair();
+        }
+        unreachable!();
+    }
+
+    /// Process a single event as if it were the next event
+    /// in the thread queue for this global scope.
+    pub fn process_event(&self, msg: CommonScriptMsg) {
+        if self.is::<Window>() {
+            return ScriptThread::process_event(msg);
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.process_event(msg);
+        }
+        unreachable!();
+    }
+
+    /// Channel to send messages to the file reading task source of
+    /// this of this global scope.
+    pub fn file_reading_task_source(&self) -> FileReadingTaskSource {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.file_reading_task_source();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.file_reading_task_source();
+        }
+        unreachable!();
+    }
+}
+
+fn timestamp_in_ms(time: Timespec) -> u64 {
+    (time.sec * 1000 + (time.nsec / 1000000) as i64) as u64
+}
+
+/// Returns the Rust global scope from a JS global object.
+#[allow(unsafe_code)]
+unsafe fn global_scope_from_global(global: *mut JSObject) -> Root<GlobalScope> {
+    assert!(!global.is_null());
+    let clasp = JS_GetClass(global);
+    assert!(((*clasp).flags & (JSCLASS_IS_DOMJSCLASS | JSCLASS_IS_GLOBAL)) != 0);
+    root_from_object(global).unwrap()
+}
diff --git a/components/script/dom/hashchangeevent.rs b/components/script/dom/hashchangeevent.rs
index 33562123ac6..0fd753c433c 100644
--- a/components/script/dom/hashchangeevent.rs
+++ b/components/script/dom/hashchangeevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::HashChangeEventBinding;
 use dom::bindings::codegen::Bindings::HashChangeEventBinding::HashChangeEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::{DOMString, USVString};
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use string_cache::Atom;
 
 // https://html.spec.whatwg.org/multipage/#hashchangeevent
@@ -31,14 +31,13 @@ impl HashChangeEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef)
-                             -> Root<HashChangeEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<HashChangeEvent> {
         reflect_dom_object(box HashChangeEvent::new_inherited(String::new(), String::new()),
                            global,
                            HashChangeEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: bool,
                cancelable: bool,
@@ -55,7 +54,7 @@ impl HashChangeEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &HashChangeEventBinding::HashChangeEventInit)
                        -> Fallible<Root<HashChangeEvent>> {
diff --git a/components/script/dom/headers.rs b/components/script/dom/headers.rs
index 7f43dd6b07a..02262dbb475 100644
--- a/components/script/dom/headers.rs
+++ b/components/script/dom/headers.rs
@@ -5,11 +5,11 @@
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::HeadersBinding::{HeadersInit, HeadersMethods, HeadersWrap};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::iterable::Iterable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, is_token};
+use dom::globalscope::GlobalScope;
 use hyper::header::Headers as HyperHeaders;
 use mime::{Mime, TopLevel, SubLevel};
 use std::cell::Cell;
@@ -43,12 +43,12 @@ impl Headers {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<Headers> {
+    pub fn new(global: &GlobalScope) -> Root<Headers> {
         reflect_dom_object(box Headers::new_inherited(), global, HeadersWrap)
     }
 
     // https://fetch.spec.whatwg.org/#dom-headers
-    pub fn Constructor(global: GlobalRef, init: Option<HeadersInit>)
+    pub fn Constructor(global: &GlobalScope, init: Option<HeadersInit>)
                        -> Fallible<Root<Headers>> {
         let dom_headers_new = Headers::new(global);
         try!(dom_headers_new.fill(init));
@@ -205,13 +205,13 @@ impl Headers {
         }
     }
 
-    pub fn for_request(global: GlobalRef) -> Root<Headers> {
+    pub fn for_request(global: &GlobalScope) -> Root<Headers> {
         let headers_for_request = Headers::new(global);
         headers_for_request.guard.set(Guard::Request);
         headers_for_request
     }
 
-    pub fn for_response(global: GlobalRef) -> Root<Headers> {
+    pub fn for_response(global: &GlobalScope) -> Root<Headers> {
         let headers_for_response = Headers::new(global);
         headers_for_response.guard.set(Guard::Response);
         headers_for_response
diff --git a/components/script/dom/history.rs b/components/script/dom/history.rs
index 5ced543d728..1a971eae009 100644
--- a/components/script/dom/history.rs
+++ b/components/script/dom/history.rs
@@ -6,9 +6,10 @@ use dom::bindings::codegen::Bindings::HistoryBinding;
 use dom::bindings::codegen::Bindings::HistoryBinding::HistoryMethods;
 use dom::bindings::codegen::Bindings::LocationBinding::LocationMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use ipc_channel::ipc;
 use msg::constellation_msg::TraversalDirection;
@@ -31,26 +32,28 @@ impl History {
 
     pub fn new(window: &Window) -> Root<History> {
         reflect_dom_object(box History::new_inherited(window),
-                           GlobalRef::Window(window),
+                           window,
                            HistoryBinding::Wrap)
     }
 }
 
 impl History {
     fn traverse_history(&self, direction: TraversalDirection) {
-        let pipeline = self.window.pipeline_id();
+        let global_scope = self.window.upcast::<GlobalScope>();
+        let pipeline = global_scope.pipeline_id();
         let msg = ConstellationMsg::TraverseHistory(Some(pipeline), direction);
-        let _ = self.window.constellation_chan().send(msg);
+        let _ = global_scope.constellation_chan().send(msg);
     }
 }
 
 impl HistoryMethods for History {
     // https://html.spec.whatwg.org/multipage/#dom-history-length
     fn Length(&self) -> u32 {
-        let pipeline = self.window.pipeline_id();
+        let global_scope = self.window.upcast::<GlobalScope>();
+        let pipeline = global_scope.pipeline_id();
         let (sender, recv) = ipc::channel().expect("Failed to create channel to send jsh length.");
         let msg = ConstellationMsg::JointSessionHistoryLength(pipeline, sender);
-        let _ = self.window.constellation_chan().send(msg);
+        let _ = global_scope.constellation_chan().send(msg);
         recv.recv().unwrap()
     }
 
diff --git a/components/script/dom/htmlbodyelement.rs b/components/script/dom/htmlbodyelement.rs
index 993d50a2a76..1cab444e871 100644
--- a/components/script/dom/htmlbodyelement.rs
+++ b/components/script/dom/htmlbodyelement.rs
@@ -13,6 +13,7 @@ use dom::bindings::str::DOMString;
 use dom::document::Document;
 use dom::element::{AttributeMutation, Element, RawLayoutElementHelpers};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, document_from_node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
@@ -137,7 +138,7 @@ impl VirtualMethods for HTMLBodyElement {
         let document = window.Document();
         document.set_reflow_timeout(time::precise_time_ns() + INITIAL_REFLOW_DELAY);
         let event = ConstellationMsg::HeadParsed;
-        window.constellation_chan().send(event).unwrap();
+        window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
     }
 
     fn parse_plain_attribute(&self, name: &Atom, value: DOMString) -> AttrValue {
diff --git a/components/script/dom/htmlcanvaselement.rs b/components/script/dom/htmlcanvaselement.rs
index f4a13836eb1..c63ab1a9531 100644
--- a/components/script/dom/htmlcanvaselement.rs
+++ b/components/script/dom/htmlcanvaselement.rs
@@ -12,7 +12,6 @@ use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLContext
 use dom::bindings::codegen::UnionTypes::CanvasRenderingContext2DOrWebGLRenderingContext;
 use dom::bindings::conversions::ConversionResult;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{HeapGCValue, JS, LayoutJS, Root};
 use dom::bindings::num::Finite;
@@ -20,6 +19,7 @@ use dom::bindings::str::DOMString;
 use dom::canvasrenderingcontext2d::{CanvasRenderingContext2D, LayoutCanvasRenderingContext2DHelpers};
 use dom::document::Document;
 use dom::element::{AttributeMutation, Element, RawLayoutElementHelpers};
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
@@ -142,7 +142,7 @@ impl HTMLCanvasElement {
         if self.context.borrow().is_none() {
             let window = window_from_node(self);
             let size = self.get_size();
-            let context = CanvasRenderingContext2D::new(GlobalRef::Window(window.r()), self, size);
+            let context = CanvasRenderingContext2D::new(window.upcast::<GlobalScope>(), self, size);
             *self.context.borrow_mut() = Some(CanvasContext::Context2d(JS::from_ref(&*context)));
         }
 
@@ -177,7 +177,7 @@ impl HTMLCanvasElement {
                 GLContextAttributes::default()
             };
 
-            let maybe_ctx = WebGLRenderingContext::new(GlobalRef::Window(window.r()), self, size, attrs);
+            let maybe_ctx = WebGLRenderingContext::new(window.upcast(), self, size, attrs);
 
             *self.context.borrow_mut() = maybe_ctx.map( |ctx| CanvasContext::WebGL(JS::from_ref(&*ctx)));
         }
diff --git a/components/script/dom/htmlcollection.rs b/components/script/dom/htmlcollection.rs
index 66a810eff9f..4274c04a21b 100644
--- a/components/script/dom/htmlcollection.rs
+++ b/components/script/dom/htmlcollection.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::HTMLCollectionBinding;
 use dom::bindings::codegen::Bindings::HTMLCollectionBinding::HTMLCollectionMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root, MutNullableHeap};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -83,7 +82,7 @@ impl HTMLCollection {
     #[allow(unrooted_must_root)]
     pub fn new(window: &Window, root: &Node, filter: Box<CollectionFilter + 'static>) -> Root<HTMLCollection> {
         reflect_dom_object(box HTMLCollection::new_inherited(root, filter),
-                           GlobalRef::Window(window), HTMLCollectionBinding::Wrap)
+                           window, HTMLCollectionBinding::Wrap)
     }
 
     pub fn create(window: &Window, root: &Node,
diff --git a/components/script/dom/htmldetailselement.rs b/components/script/dom/htmldetailselement.rs
index 61f02d0899f..9a7cf6e13f8 100644
--- a/components/script/dom/htmldetailselement.rs
+++ b/components/script/dom/htmldetailselement.rs
@@ -5,7 +5,6 @@
 use dom::attr::Attr;
 use dom::bindings::codegen::Bindings::HTMLDetailsElementBinding;
 use dom::bindings::codegen::Bindings::HTMLDetailsElementBinding::HTMLDetailsElementMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
@@ -79,7 +78,7 @@ impl VirtualMethods for HTMLDetailsElement {
                 element: details,
                 toggle_number: counter
             };
-            let _ = task_source.queue(runnable, GlobalRef::Window(&window));
+            let _ = task_source.queue(runnable, window.upcast());
         }
     }
 }
diff --git a/components/script/dom/htmlformcontrolscollection.rs b/components/script/dom/htmlformcontrolscollection.rs
index e52a541225f..3986692099c 100644
--- a/components/script/dom/htmlformcontrolscollection.rs
+++ b/components/script/dom/htmlformcontrolscollection.rs
@@ -6,7 +6,6 @@ use dom::bindings::codegen::Bindings::HTMLCollectionBinding::HTMLCollectionMetho
 use dom::bindings::codegen::Bindings::HTMLFormControlsCollectionBinding;
 use dom::bindings::codegen::Bindings::HTMLFormControlsCollectionBinding::HTMLFormControlsCollectionMethods;
 use dom::bindings::codegen::UnionTypes::RadioNodeListOrElement;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -33,7 +32,7 @@ impl HTMLFormControlsCollection {
         -> Root<HTMLFormControlsCollection>
     {
         reflect_dom_object(box HTMLFormControlsCollection::new_inherited(root, filter),
-                           GlobalRef::Window(window),
+                           window,
                            HTMLFormControlsCollectionBinding::Wrap)
     }
 
@@ -67,7 +66,6 @@ impl HTMLFormControlsCollectionMethods for HTMLFormControlsCollection {
                 let once = iter::once(Root::upcast::<Node>(elem));
                 let list = once.chain(peekable.map(Root::upcast));
                 let global = self.global();
-                let global = global.r();
                 let window = global.as_window();
                 Some(RadioNodeListOrElement::RadioNodeList(RadioNodeList::new_simple_list(window, list)))
             }
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 8759fbafe5e..e1c53a41e12 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -12,7 +12,6 @@ use dom::bindings::codegen::Bindings::HTMLFormElementBinding::HTMLFormElementMet
 use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementMethods;
 use dom::bindings::codegen::Bindings::HTMLTextAreaElementBinding::HTMLTextAreaElementMethods;
 use dom::bindings::conversions::DerivedFrom;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::refcounted::Trusted;
@@ -24,6 +23,7 @@ use dom::element::Element;
 use dom::event::{EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
 use dom::file::File;
+use dom::globalscope::GlobalScope;
 use dom::htmlbuttonelement::HTMLButtonElement;
 use dom::htmlcollection::CollectionFilter;
 use dom::htmldatalistelement::HTMLDataListElement;
@@ -436,14 +436,14 @@ impl HTMLFormElement {
         // Step 2
         let nav = box PlannedNavigation {
             load_data: load_data,
-            pipeline_id: window.pipeline_id(),
+            pipeline_id: window.upcast::<GlobalScope>().pipeline_id(),
             script_chan: window.main_thread_script_chan().clone(),
             generation_id: self.generation_id.get(),
             form: Trusted::new(self)
         };
 
         // Step 3
-        window.dom_manipulation_task_source().queue(nav, GlobalRef::Window(&window)).unwrap();
+        window.dom_manipulation_task_source().queue(nav, window.upcast()).unwrap();
     }
 
     /// Interactively validate the constraints of form elements
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index 1503ff28e06..75d828e73c9 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -18,7 +18,6 @@ use dom::bindings::codegen::Bindings::HTMLIFrameElementBinding::HTMLIFrameElemen
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::conversions::ToJSValConvertible;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap, Root};
 use dom::bindings::reflector::Reflectable;
@@ -30,6 +29,7 @@ use dom::domtokenlist::DOMTokenList;
 use dom::element::{AttributeMutation, Element, RawLayoutElementHelpers};
 use dom::event::Event;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, NodeDamage, UnbindContext, document_from_node, window_from_node};
 use dom::urlhelper::UrlHelper;
@@ -126,9 +126,10 @@ impl HTMLIFrameElement {
         let private_iframe = self.privatebrowsing();
         let frame_type = if self.Mozbrowser() { FrameType::MozBrowserIFrame } else { FrameType::IFrame };
 
+        let global_scope = window.upcast::<GlobalScope>();
         let load_info = IFrameLoadInfo {
             load_data: load_data,
-            parent_pipeline_id: window.pipeline_id(),
+            parent_pipeline_id: global_scope.pipeline_id(),
             old_pipeline_id: old_pipeline_id,
             new_pipeline_id: new_pipeline_id,
             sandbox: sandboxed,
@@ -136,7 +137,8 @@ impl HTMLIFrameElement {
             frame_type: frame_type,
             replace: replace,
         };
-        window.constellation_chan()
+        global_scope
+              .constellation_chan()
               .send(ConstellationMsg::ScriptLoadedURLInIFrame(load_info))
               .unwrap();
 
@@ -217,7 +219,7 @@ impl HTMLIFrameElement {
             let window = window_from_node(self);
             let window = window.r();
             let msg = ConstellationMsg::SetVisible(pipeline_id, visible);
-            window.constellation_chan().send(msg).unwrap();
+            window.upcast::<GlobalScope>().constellation_chan().send(msg).unwrap();
         }
     }
 
@@ -316,7 +318,7 @@ pub fn build_mozbrowser_custom_event(window: &Window, event: MozBrowserEvent) ->
     rooted!(in(cx) let mut detail = UndefinedValue());
     let event_name = Atom::from(event.name());
     unsafe { build_mozbrowser_event_detail(event, cx, detail.handle_mut()); }
-    CustomEvent::new(GlobalRef::Window(window),
+    CustomEvent::new(window.upcast(),
                      event_name,
                      true,
                      true,
@@ -408,7 +410,7 @@ pub fn Navigate(iframe: &HTMLIFrameElement, direction: TraversalDirection) -> Er
         if iframe.upcast::<Node>().is_in_doc() {
             let window = window_from_node(iframe);
             let msg = ConstellationMsg::TraverseHistory(iframe.pipeline_id(), direction);
-            window.constellation_chan().send(msg).unwrap();
+            window.upcast::<GlobalScope>().constellation_chan().send(msg).unwrap();
         }
 
         Ok(())
@@ -642,7 +644,7 @@ impl VirtualMethods for HTMLIFrameElement {
                 (Some(sender), Some(receiver))
             };
             let msg = ConstellationMsg::RemoveIFrame(pipeline_id, sender);
-            window.constellation_chan().send(msg).unwrap();
+            window.upcast::<GlobalScope>().constellation_chan().send(msg).unwrap();
             if let Some(receiver) = receiver {
                 receiver.recv().unwrap()
             }
diff --git a/components/script/dom/htmlimageelement.rs b/components/script/dom/htmlimageelement.rs
index c6652913c42..428cfb97343 100644
--- a/components/script/dom/htmlimageelement.rs
+++ b/components/script/dom/htmlimageelement.rs
@@ -9,7 +9,6 @@ use dom::bindings::codegen::Bindings::HTMLImageElementBinding;
 use dom::bindings::codegen::Bindings::HTMLImageElementBinding::HTMLImageElementMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{LayoutJS, Root};
 use dom::bindings::refcounted::Trusted;
@@ -17,6 +16,7 @@ use dom::bindings::str::DOMString;
 use dom::document::Document;
 use dom::element::{AttributeMutation, Element, RawLayoutElementHelpers};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, NodeDamage, document_from_node, window_from_node};
 use dom::values::UNSIGNED_LONG_MAX;
@@ -191,7 +191,7 @@ impl HTMLImageElement {
                         src: src.into(),
                     };
                     let task = window.dom_manipulation_task_source();
-                    let _ = task.queue(runnable, GlobalRef::Window(window));
+                    let _ = task.queue(runnable, window.upcast());
                 }
             }
         }
@@ -225,7 +225,7 @@ impl HTMLImageElement {
                            HTMLImageElementBinding::Wrap)
     }
 
-    pub fn Image(global: GlobalRef,
+    pub fn Image(global: &GlobalScope,
                  width: Option<u32>,
                  height: Option<u32>) -> Fallible<Root<HTMLImageElement>> {
         let document = global.as_window().Document();
diff --git a/components/script/dom/htmlinputelement.rs b/components/script/dom/htmlinputelement.rs
index d9cda98b284..ab184463bb2 100644
--- a/components/script/dom/htmlinputelement.rs
+++ b/components/script/dom/htmlinputelement.rs
@@ -21,6 +21,7 @@ use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
 use dom::file::File;
 use dom::filelist::FileList;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::htmlfieldsetelement::HTMLFieldSetElement;
 use dom::htmlformelement::{FormControl, FormDatum, FormDatumValue, FormSubmitter, HTMLFormElement};
@@ -128,7 +129,7 @@ static DEFAULT_MIN_LENGTH: i32 = -1;
 
 impl HTMLInputElement {
     fn new_inherited(local_name: Atom, prefix: Option<DOMString>, document: &Document) -> HTMLInputElement {
-        let chan = document.window().constellation_chan().clone();
+        let chan = document.window().upcast::<GlobalScope>().constellation_chan().clone();
         HTMLInputElement {
             htmlelement:
                 HTMLElement::new_inherited_with_state(IN_ENABLED_STATE | IN_READ_WRITE_STATE,
@@ -794,7 +795,7 @@ impl HTMLInputElement {
     fn select_files(&self, opt_test_paths: Option<Vec<DOMString>>) {
         let window = window_from_node(self);
         let origin = get_blob_origin(&window.get_url());
-        let resource_threads = window.resource_threads();
+        let resource_threads = window.upcast::<GlobalScope>().resource_threads();
 
         let mut files: Vec<Root<File>> = vec![];
         let mut error = None;
diff --git a/components/script/dom/htmllinkelement.rs b/components/script/dom/htmllinkelement.rs
index b02aa0ad6a7..937bdc410d4 100644
--- a/components/script/dom/htmllinkelement.rs
+++ b/components/script/dom/htmllinkelement.rs
@@ -18,6 +18,7 @@ use dom::document::Document;
 use dom::domtokenlist::DOMTokenList;
 use dom::element::{AttributeMutation, Element, ElementCreator};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, document_from_node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
@@ -266,7 +267,7 @@ impl HTMLLinkElement {
             credentials_mode: CredentialsMode::Include,
             use_url_credentials: true,
             origin: document.url().clone(),
-            pipeline_id: Some(self.global().r().pipeline_id()),
+            pipeline_id: Some(self.global().pipeline_id()),
             referrer_url: Some(document.url().clone()),
             referrer_policy: referrer_policy,
             .. RequestInit::default()
@@ -280,7 +281,7 @@ impl HTMLLinkElement {
         match document.base_url().join(href) {
             Ok(url) => {
                 let event = ConstellationMsg::NewFavicon(url.clone());
-                document.window().constellation_chan().send(event).unwrap();
+                document.window().upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
 
                 let mozbrowser_event = match *sizes {
                     Some(ref sizes) => MozBrowserEvent::IconChange(rel.to_owned(), url.to_string(), sizes.to_owned()),
diff --git a/components/script/dom/htmlmediaelement.rs b/components/script/dom/htmlmediaelement.rs
index 5bbdd738079..31140185ce2 100644
--- a/components/script/dom/htmlmediaelement.rs
+++ b/components/script/dom/htmlmediaelement.rs
@@ -12,7 +12,6 @@ use dom::bindings::codegen::Bindings::HTMLMediaElementBinding::HTMLMediaElementC
 use dom::bindings::codegen::Bindings::HTMLMediaElementBinding::HTMLMediaElementMethods;
 use dom::bindings::codegen::Bindings::MediaErrorBinding::MediaErrorConstants::*;
 use dom::bindings::codegen::Bindings::MediaErrorBinding::MediaErrorMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, MutNullableHeap, JS};
 use dom::bindings::refcounted::Trusted;
@@ -276,7 +275,7 @@ impl HTMLMediaElement {
             elem: Trusted::new(self),
         };
         let win = window_from_node(self);
-        let _ = win.dom_manipulation_task_source().queue(task, GlobalRef::Window(&win));
+        let _ = win.dom_manipulation_task_source().queue(task, win.upcast());
     }
 
     // https://html.spec.whatwg.org/multipage/#internal-pause-steps step 2.2
@@ -300,18 +299,18 @@ impl HTMLMediaElement {
             elem: Trusted::new(self),
         };
         let win = window_from_node(self);
-        let _ = win.dom_manipulation_task_source().queue(task, GlobalRef::Window(&win));
+        let _ = win.dom_manipulation_task_source().queue(task, win.upcast());
     }
 
     fn queue_fire_simple_event(&self, type_: &'static str) {
         let win = window_from_node(self);
         let task = box FireSimpleEventTask::new(self, type_);
-        let _ = win.dom_manipulation_task_source().queue(task, GlobalRef::Window(&win));
+        let _ = win.dom_manipulation_task_source().queue(task, win.upcast());
     }
 
     fn fire_simple_event(&self, type_: &str) {
         let window = window_from_node(self);
-        let event = Event::new(GlobalRef::Window(&*window),
+        let event = Event::new(window.upcast(),
                                Atom::from(type_),
                                EventBubbles::DoesNotBubble,
                                EventCancelable::NotCancelable);
@@ -533,8 +532,8 @@ impl HTMLMediaElement {
 
     fn queue_dedicated_media_source_failure_steps(&self) {
         let window = window_from_node(self);
-        let _ = window.dom_manipulation_task_source().queue(box DedicatedMediaSourceFailureTask::new(self),
-                                                            GlobalRef::Window(&window));
+        let _ = window.dom_manipulation_task_source().queue(
+            box DedicatedMediaSourceFailureTask::new(self), window.upcast());
     }
 
     // https://html.spec.whatwg.org/multipage/#dedicated-media-source-failure-steps
diff --git a/components/script/dom/htmloptionscollection.rs b/components/script/dom/htmloptionscollection.rs
index dd6d4531974..473d698d35b 100644
--- a/components/script/dom/htmloptionscollection.rs
+++ b/components/script/dom/htmloptionscollection.rs
@@ -9,7 +9,6 @@ use dom::bindings::codegen::Bindings::HTMLOptionsCollectionBinding::HTMLOptionsC
 use dom::bindings::codegen::Bindings::NodeBinding::NodeBinding::NodeMethods;
 use dom::bindings::codegen::UnionTypes::{HTMLOptionElementOrHTMLOptGroupElement, HTMLElementOrLong};
 use dom::bindings::error::{Error, ErrorResult};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
@@ -36,7 +35,7 @@ impl HTMLOptionsCollection {
         -> Root<HTMLOptionsCollection>
     {
         reflect_dom_object(box HTMLOptionsCollection::new_inherited(root, filter),
-                           GlobalRef::Window(window),
+                           window,
                            HTMLOptionsCollectionBinding::Wrap)
     }
 
diff --git a/components/script/dom/htmlscriptelement.rs b/components/script/dom/htmlscriptelement.rs
index e96ceb6d834..fa1604ffc2b 100644
--- a/components/script/dom/htmlscriptelement.rs
+++ b/components/script/dom/htmlscriptelement.rs
@@ -10,7 +10,6 @@ use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::HTMLScriptElementBinding;
 use dom::bindings::codegen::Bindings::HTMLScriptElementBinding::HTMLScriptElementMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::js::RootedReference;
@@ -21,6 +20,7 @@ use dom::document::Document;
 use dom::element::{AttributeMutation, Element, ElementCreator};
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventdispatcher::EventStatus;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::node::{ChildrenMutation, CloneChildrenFlag, Node};
 use dom::node::{document_from_node, window_from_node};
@@ -242,7 +242,7 @@ fn fetch_a_classic_script(script: &HTMLScriptElement,
             _ => CredentialsMode::Include,
         },
         origin: doc.url().clone(),
-        pipeline_id: Some(script.global().r().pipeline_id()),
+        pipeline_id: Some(script.global().pipeline_id()),
         referrer_url: Some(doc.url().clone()),
         referrer_policy: doc.get_referrer_policy(),
         .. RequestInit::default()
@@ -504,7 +504,7 @@ impl HTMLScriptElement {
         // Step 5.a.2.
         let window = window_from_node(self);
         rooted!(in(window.get_cx()) let mut rval = UndefinedValue());
-        GlobalRef::Window(&window).evaluate_script_on_global_with_result(
+        window.upcast::<GlobalScope>().evaluate_script_on_global_with_result(
             &script.text, script.url.as_str(), rval.handle_mut());
 
         // Step 6.
@@ -604,7 +604,7 @@ impl HTMLScriptElement {
                       cancelable: EventCancelable) -> EventStatus {
         let window = window_from_node(self);
         let window = window.r();
-        let event = Event::new(GlobalRef::Window(window), type_, bubbles, cancelable);
+        let event = Event::new(window.upcast(), type_, bubbles, cancelable);
         event.fire(self.upcast())
     }
 }
diff --git a/components/script/dom/htmltextareaelement.rs b/components/script/dom/htmltextareaelement.rs
index 3a4418d713d..bcdb8268c61 100644
--- a/components/script/dom/htmltextareaelement.rs
+++ b/components/script/dom/htmltextareaelement.rs
@@ -15,6 +15,7 @@ use dom::document::Document;
 use dom::element::{AttributeMutation, Element};
 use dom::element::RawLayoutElementHelpers;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::htmlfieldsetelement::HTMLFieldSetElement;
 use dom::htmlformelement::{FormControl, HTMLFormElement};
@@ -99,7 +100,7 @@ impl HTMLTextAreaElement {
     fn new_inherited(local_name: Atom,
                      prefix: Option<DOMString>,
                      document: &Document) -> HTMLTextAreaElement {
-        let chan = document.window().constellation_chan().clone();
+        let chan = document.window().upcast::<GlobalScope>().constellation_chan().clone();
         HTMLTextAreaElement {
             htmlelement:
                 HTMLElement::new_inherited_with_state(IN_ENABLED_STATE | IN_READ_WRITE_STATE,
diff --git a/components/script/dom/imagedata.rs b/components/script/dom/imagedata.rs
index 0959a52eb32..5f99fb9db57 100644
--- a/components/script/dom/imagedata.rs
+++ b/components/script/dom/imagedata.rs
@@ -5,9 +5,9 @@
 use core::nonzero::NonZero;
 use dom::bindings::codegen::Bindings::ImageDataBinding;
 use dom::bindings::codegen::Bindings::ImageDataBinding::ImageDataMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use euclid::size::Size2D;
 use js::jsapi::{Heap, JSContext, JSObject};
 use js::jsapi::{JS_GetUint8ClampedArrayData, JS_NewUint8ClampedArray};
@@ -27,7 +27,7 @@ pub struct ImageData {
 
 impl ImageData {
     #[allow(unsafe_code)]
-    pub fn new(global: GlobalRef, width: u32, height: u32, data: Option<Vec<u8>>) -> Root<ImageData> {
+    pub fn new(global: &GlobalScope, width: u32, height: u32, data: Option<Vec<u8>>) -> Root<ImageData> {
         let mut imagedata = box ImageData {
             reflector_: Reflector::new(),
             width: width,
diff --git a/components/script/dom/keyboardevent.rs b/components/script/dom/keyboardevent.rs
index d21f53eb609..4da24309e18 100644
--- a/components/script/dom/keyboardevent.rs
+++ b/components/script/dom/keyboardevent.rs
@@ -7,12 +7,12 @@ use dom::bindings::codegen::Bindings::KeyboardEventBinding;
 use dom::bindings::codegen::Bindings::KeyboardEventBinding::{KeyboardEventConstants, KeyboardEventMethods};
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use dom::uievent::UIEvent;
 use dom::window::Window;
 use msg::constellation_msg;
@@ -62,7 +62,7 @@ impl KeyboardEvent {
 
     pub fn new_uninitialized(window: &Window) -> Root<KeyboardEvent> {
         reflect_dom_object(box KeyboardEvent::new_inherited(),
-                           GlobalRef::Window(window),
+                           window,
                            KeyboardEventBinding::Wrap)
     }
 
@@ -101,10 +101,11 @@ impl KeyboardEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &KeyboardEventBinding::KeyboardEventInit) -> Fallible<Root<KeyboardEvent>> {
-        let event = KeyboardEvent::new(global.as_window(), type_,
+        let event = KeyboardEvent::new(global.as_window(),
+                                       type_,
                                        init.parent.parent.parent.bubbles,
                                        init.parent.parent.parent.cancelable,
                                        init.parent.parent.view.r(),
diff --git a/components/script/dom/location.rs b/components/script/dom/location.rs
index ba835ada146..cf91c683f2f 100644
--- a/components/script/dom/location.rs
+++ b/components/script/dom/location.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::LocationBinding;
 use dom::bindings::codegen::Bindings::LocationBinding::LocationMethods;
 use dom::bindings::error::{Error, ErrorResult};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
@@ -29,7 +28,7 @@ impl Location {
 
     pub fn new(window: &Window) -> Root<Location> {
         reflect_dom_object(box Location::new_inherited(window),
-                           GlobalRef::Window(window),
+                           window,
                            LocationBinding::Wrap)
     }
 
diff --git a/components/script/dom/mediaerror.rs b/components/script/dom/mediaerror.rs
index 17d92947f72..b7b7a800989 100644
--- a/components/script/dom/mediaerror.rs
+++ b/components/script/dom/mediaerror.rs
@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::Bindings::MediaErrorBinding::{self, MediaErrorMethods};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::window::Window;
@@ -24,7 +23,7 @@ impl MediaError {
 
     pub fn new(window: &Window, code: u16) -> Root<MediaError> {
         reflect_dom_object(box MediaError::new_inherited(code),
-                           GlobalRef::Window(window),
+                           window,
                            MediaErrorBinding::Wrap)
     }
 }
diff --git a/components/script/dom/messageevent.rs b/components/script/dom/messageevent.rs
index b5b46fba5d8..53143711cf0 100644
--- a/components/script/dom/messageevent.rs
+++ b/components/script/dom/messageevent.rs
@@ -6,13 +6,13 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::MessageEventBinding;
 use dom::bindings::codegen::Bindings::MessageEventBinding::MessageEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, Heap, JSContext};
 use js::jsval::JSVal;
 use std::default::Default;
@@ -27,14 +27,14 @@ pub struct MessageEvent {
 }
 
 impl MessageEvent {
-    pub fn new_uninitialized(global: GlobalRef) -> Root<MessageEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<MessageEvent> {
         MessageEvent::new_initialized(global,
                                       HandleValue::undefined(),
                                       DOMString::new(),
                                       DOMString::new())
     }
 
-    pub fn new_initialized(global: GlobalRef,
+    pub fn new_initialized(global: &GlobalScope,
                            data: HandleValue,
                            origin: DOMString,
                            lastEventId: DOMString) -> Root<MessageEvent> {
@@ -48,7 +48,7 @@ impl MessageEvent {
         reflect_dom_object(ev, global, MessageEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef, type_: Atom,
+    pub fn new(global: &GlobalScope, type_: Atom,
                bubbles: bool, cancelable: bool,
                data: HandleValue, origin: DOMString, lastEventId: DOMString)
                -> Root<MessageEvent> {
@@ -60,27 +60,36 @@ impl MessageEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &MessageEventBinding::MessageEventInit)
                        -> Fallible<Root<MessageEvent>> {
         // Dictionaries need to be rooted
         // https://github.com/servo/servo/issues/6381
         rooted!(in(global.get_cx()) let data = init.data);
-        let ev = MessageEvent::new(global, Atom::from(type_), init.parent.bubbles, init.parent.cancelable,
+        let ev = MessageEvent::new(global,
+                                   Atom::from(type_),
+                                   init.parent.bubbles,
+                                   init.parent.cancelable,
                                    data.handle(),
-                                   init.origin.clone(), init.lastEventId.clone());
+                                   init.origin.clone(),
+                                   init.lastEventId.clone());
         Ok(ev)
     }
 }
 
 impl MessageEvent {
     pub fn dispatch_jsval(target: &EventTarget,
-                          scope: GlobalRef,
+                          scope: &GlobalScope,
                           message: HandleValue) {
         let messageevent = MessageEvent::new(
-            scope, atom!("message"), false, false, message,
-            DOMString::new(), DOMString::new());
+            scope,
+            atom!("message"),
+            false,
+            false,
+            message,
+            DOMString::new(),
+            DOMString::new());
         messageevent.upcast::<Event>().fire(target);
     }
 }
diff --git a/components/script/dom/mimetypearray.rs b/components/script/dom/mimetypearray.rs
index de820f6d06a..e0dd8090f8f 100644
--- a/components/script/dom/mimetypearray.rs
+++ b/components/script/dom/mimetypearray.rs
@@ -4,10 +4,10 @@
 
 use dom::bindings::codegen::Bindings::MimeTypeArrayBinding;
 use dom::bindings::codegen::Bindings::MimeTypeArrayBinding::MimeTypeArrayMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use dom::mimetype::MimeType;
 
 #[dom_struct]
@@ -22,7 +22,7 @@ impl MimeTypeArray {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<MimeTypeArray> {
+    pub fn new(global: &GlobalScope) -> Root<MimeTypeArray> {
         reflect_dom_object(box MimeTypeArray::new_inherited(),
                            global,
                            MimeTypeArrayBinding::Wrap)
diff --git a/components/script/dom/mod.rs b/components/script/dom/mod.rs
index 0081efba21c..2335f8a0a25 100644
--- a/components/script/dom/mod.rs
+++ b/components/script/dom/mod.rs
@@ -276,6 +276,7 @@ pub mod filereadersync;
 pub mod focusevent;
 pub mod forcetouchevent;
 pub mod formdata;
+pub mod globalscope;
 pub mod hashchangeevent;
 pub mod headers;
 pub mod history;
diff --git a/components/script/dom/mouseevent.rs b/components/script/dom/mouseevent.rs
index 659a28226b7..27a61c79400 100644
--- a/components/script/dom/mouseevent.rs
+++ b/components/script/dom/mouseevent.rs
@@ -6,13 +6,13 @@ use dom::bindings::codegen::Bindings::MouseEventBinding;
 use dom::bindings::codegen::Bindings::MouseEventBinding::MouseEventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::uievent::UIEvent;
 use dom::window::Window;
 use std::cell::Cell;
@@ -53,7 +53,7 @@ impl MouseEvent {
 
     pub fn new_uninitialized(window: &Window) -> Root<MouseEvent> {
         reflect_dom_object(box MouseEvent::new_inherited(),
-                           GlobalRef::Window(window),
+                           window,
                            MouseEventBinding::Wrap)
     }
 
@@ -82,12 +82,13 @@ impl MouseEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &MouseEventBinding::MouseEventInit) -> Fallible<Root<MouseEvent>> {
         let bubbles = EventBubbles::from(init.parent.parent.parent.bubbles);
         let cancelable = EventCancelable::from(init.parent.parent.parent.cancelable);
-        let event = MouseEvent::new(global.as_window(), type_,
+        let event = MouseEvent::new(global.as_window(),
+                                    type_,
                                     bubbles,
                                     cancelable,
                                     init.parent.parent.view.r(),
diff --git a/components/script/dom/namednodemap.rs b/components/script/dom/namednodemap.rs
index 9edc1b1e93b..1145ff60562 100644
--- a/components/script/dom/namednodemap.rs
+++ b/components/script/dom/namednodemap.rs
@@ -7,7 +7,6 @@ use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::NamedNodeMapBinding;
 use dom::bindings::codegen::Bindings::NamedNodeMapBinding::NamedNodeMapMethods;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -33,7 +32,7 @@ impl NamedNodeMap {
 
     pub fn new(window: &Window, elem: &Element) -> Root<NamedNodeMap> {
         reflect_dom_object(box NamedNodeMap::new_inherited(elem),
-                           GlobalRef::Window(window), NamedNodeMapBinding::Wrap)
+                           window, NamedNodeMapBinding::Wrap)
     }
 }
 
diff --git a/components/script/dom/navigator.rs b/components/script/dom/navigator.rs
index ce97c30ae60..bea18dfe61b 100644
--- a/components/script/dom/navigator.rs
+++ b/components/script/dom/navigator.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::NavigatorBinding;
 use dom::bindings::codegen::Bindings::NavigatorBinding::NavigatorMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflector, Reflectable, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -37,7 +36,7 @@ impl Navigator {
 
     pub fn new(window: &Window) -> Root<Navigator> {
         reflect_dom_object(box Navigator::new_inherited(),
-                           GlobalRef::Window(window),
+                           window,
                            NavigatorBinding::Wrap)
     }
 }
@@ -80,7 +79,7 @@ impl NavigatorMethods for Navigator {
 
     // https://webbluetoothcg.github.io/web-bluetooth/#dom-navigator-bluetooth
     fn Bluetooth(&self) -> Root<Bluetooth> {
-        self.bluetooth.or_init(|| Bluetooth::new(self.global().r()))
+        self.bluetooth.or_init(|| Bluetooth::new(&self.global()))
     }
 
     // https://html.spec.whatwg.org/multipage/#navigatorlanguage
@@ -90,12 +89,12 @@ impl NavigatorMethods for Navigator {
 
     // https://html.spec.whatwg.org/multipage/#dom-navigator-plugins
     fn Plugins(&self) -> Root<PluginArray> {
-        self.plugins.or_init(|| PluginArray::new(self.global().r()))
+        self.plugins.or_init(|| PluginArray::new(&self.global()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-navigator-mimetypes
     fn MimeTypes(&self) -> Root<MimeTypeArray> {
-        self.mime_types.or_init(|| MimeTypeArray::new(self.global().r()))
+        self.mime_types.or_init(|| MimeTypeArray::new(&self.global()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-navigator-javaenabled
@@ -105,7 +104,9 @@ impl NavigatorMethods for Navigator {
 
     // https://w3c.github.io/ServiceWorker/#navigator-service-worker-attribute
     fn ServiceWorker(&self) -> Root<ServiceWorkerContainer> {
-        self.service_worker.or_init(|| ServiceWorkerContainer::new(self.global().r()))
+        self.service_worker.or_init(|| {
+            ServiceWorkerContainer::new(&self.global())
+        })
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-navigator-cookieenabled
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 041d6407418..c18613ac6a2 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -20,7 +20,6 @@ use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::UnionTypes::NodeOrString;
 use dom::bindings::conversions::{self, DerivedFrom};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::{Castable, CharacterDataTypeId, ElementTypeId};
 use dom::bindings::inheritance::{EventTargetTypeId, HTMLElementTypeId, NodeTypeId};
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap};
@@ -35,6 +34,7 @@ use dom::documentfragment::DocumentFragment;
 use dom::documenttype::DocumentType;
 use dom::element::{Element, ElementCreator};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::htmlbodyelement::HTMLBodyElement;
 use dom::htmlcanvaselement::LayoutHTMLCanvasElementHelpers;
 use dom::htmlcollection::HTMLCollection;
@@ -1339,13 +1339,15 @@ pub enum CloneChildrenFlag {
 fn as_uintptr<T>(t: &T) -> uintptr_t { t as *const T as uintptr_t }
 
 impl Node {
-    pub fn reflect_node<N: DerivedFrom<Node> + Reflectable>
-            (node:      Box<N>,
-             document:  &Document,
-             wrap_fn:   extern "Rust" fn(*mut JSContext, GlobalRef, Box<N>) -> Root<N>)
-             -> Root<N> {
+    pub fn reflect_node<N>(
+            node: Box<N>,
+            document: &Document,
+            wrap_fn: extern "Rust" fn(*mut JSContext, &GlobalScope, Box<N>) -> Root<N>)
+            -> Root<N>
+        where N: DerivedFrom<Node> + Reflectable
+    {
         let window = document.window();
-        reflect_dom_object(node, GlobalRef::Window(window), wrap_fn)
+        reflect_dom_object(node, window, wrap_fn)
     }
 
     pub fn new_inherited(doc: &Document) -> Node {
diff --git a/components/script/dom/nodeiterator.rs b/components/script/dom/nodeiterator.rs
index 14b8f240fbb..4315dd28113 100644
--- a/components/script/dom/nodeiterator.rs
+++ b/components/script/dom/nodeiterator.rs
@@ -9,7 +9,6 @@ use dom::bindings::codegen::Bindings::NodeFilterBinding::NodeFilterConstants;
 use dom::bindings::codegen::Bindings::NodeIteratorBinding;
 use dom::bindings::codegen::Bindings::NodeIteratorBinding::NodeIteratorMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::document::Document;
@@ -48,7 +47,7 @@ impl NodeIterator {
                            what_to_show: u32,
                            filter: Filter) -> Root<NodeIterator> {
         reflect_dom_object(box NodeIterator::new_inherited(root_node, what_to_show, filter),
-                           GlobalRef::Window(document.window()),
+                           document.window(),
                            NodeIteratorBinding::Wrap)
     }
 
diff --git a/components/script/dom/nodelist.rs b/components/script/dom/nodelist.rs
index 8f8a5515592..ffd44d277a5 100644
--- a/components/script/dom/nodelist.rs
+++ b/components/script/dom/nodelist.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::NodeListBinding;
 use dom::bindings::codegen::Bindings::NodeListBinding::NodeListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::node::{ChildrenMutation, Node};
@@ -38,7 +37,8 @@ impl NodeList {
     #[allow(unrooted_must_root)]
     pub fn new(window: &Window, list_type: NodeListType) -> Root<NodeList> {
         reflect_dom_object(box NodeList::new_inherited(list_type),
-                           GlobalRef::Window(window), NodeListBinding::Wrap)
+                           window,
+                           NodeListBinding::Wrap)
     }
 
     pub fn new_simple_list<T>(window: &Window, iter: T) -> Root<NodeList>
diff --git a/components/script/dom/pagetransitionevent.rs b/components/script/dom/pagetransitionevent.rs
index 7c6b7b6f555..883f3319394 100644
--- a/components/script/dom/pagetransitionevent.rs
+++ b/components/script/dom/pagetransitionevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::PageTransitionEventBinding;
 use dom::bindings::codegen::Bindings::PageTransitionEventBinding::PageTransitionEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use std::cell::Cell;
 use string_cache::Atom;
 
@@ -30,13 +30,13 @@ impl PageTransitionEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<PageTransitionEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<PageTransitionEvent> {
         reflect_dom_object(box PageTransitionEvent::new_inherited(),
                            global,
                            PageTransitionEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: bool,
                cancelable: bool,
@@ -51,7 +51,7 @@ impl PageTransitionEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &PageTransitionEventBinding::PageTransitionEventInit)
                        -> Fallible<Root<PageTransitionEvent>> {
diff --git a/components/script/dom/performance.rs b/components/script/dom/performance.rs
index f6bc8d288f8..3852a49b28c 100644
--- a/components/script/dom/performance.rs
+++ b/components/script/dom/performance.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::PerformanceBinding;
 use dom::bindings::codegen::Bindings::PerformanceBinding::PerformanceMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::num::Finite;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -38,7 +37,7 @@ impl Performance {
         reflect_dom_object(box Performance::new_inherited(window,
                                                           navigation_start,
                                                           navigation_start_precise),
-                           GlobalRef::Window(window),
+                           window,
                            PerformanceBinding::Wrap)
     }
 }
diff --git a/components/script/dom/performancetiming.rs b/components/script/dom/performancetiming.rs
index 6faa8246242..16dc7650649 100644
--- a/components/script/dom/performancetiming.rs
+++ b/components/script/dom/performancetiming.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::PerformanceTimingBinding;
 use dom::bindings::codegen::Bindings::PerformanceTimingBinding::PerformanceTimingMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::document::Document;
@@ -40,7 +39,8 @@ impl PerformanceTiming {
         let timing = PerformanceTiming::new_inherited(navigation_start,
                                                       navigation_start_precise,
                                                       window.Document().r());
-        reflect_dom_object(box timing, GlobalRef::Window(window),
+        reflect_dom_object(box timing,
+                           window,
                            PerformanceTimingBinding::Wrap)
     }
 }
diff --git a/components/script/dom/pluginarray.rs b/components/script/dom/pluginarray.rs
index aa6b779280d..fde760d793c 100644
--- a/components/script/dom/pluginarray.rs
+++ b/components/script/dom/pluginarray.rs
@@ -4,10 +4,10 @@
 
 use dom::bindings::codegen::Bindings::PluginArrayBinding;
 use dom::bindings::codegen::Bindings::PluginArrayBinding::PluginArrayMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use dom::plugin::Plugin;
 
 #[dom_struct]
@@ -22,7 +22,7 @@ impl PluginArray {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<PluginArray> {
+    pub fn new(global: &GlobalScope) -> Root<PluginArray> {
         reflect_dom_object(box PluginArray::new_inherited(),
                            global,
                            PluginArrayBinding::Wrap)
diff --git a/components/script/dom/popstateevent.rs b/components/script/dom/popstateevent.rs
index a9487f48299..7b7af62a6fe 100644
--- a/components/script/dom/popstateevent.rs
+++ b/components/script/dom/popstateevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::PopStateEventBinding;
 use dom::bindings::codegen::Bindings::PopStateEventBinding::PopStateEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{MutHeapJSVal, Root};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, JSContext};
 use js::jsval::JSVal;
 use string_cache::Atom;
@@ -32,13 +32,13 @@ impl PopStateEvent {
         }
     }
 
-    pub fn new_uninitialized(global: GlobalRef) -> Root<PopStateEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<PopStateEvent> {
         reflect_dom_object(box PopStateEvent::new_inherited(),
                            global,
                            PopStateEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: bool,
                cancelable: bool,
@@ -54,7 +54,7 @@ impl PopStateEvent {
     }
 
     #[allow(unsafe_code)]
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &PopStateEventBinding::PopStateEventInit)
                        -> Fallible<Root<PopStateEvent>> {
diff --git a/components/script/dom/progressevent.rs b/components/script/dom/progressevent.rs
index f0d2b5c400a..189f65412fe 100644
--- a/components/script/dom/progressevent.rs
+++ b/components/script/dom/progressevent.rs
@@ -6,13 +6,12 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::ProgressEventBinding;
 use dom::bindings::codegen::Bindings::ProgressEventBinding::ProgressEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
-use dom::window::Window;
+use dom::globalscope::GlobalScope;
 use string_cache::Atom;
 
 #[dom_struct]
@@ -32,12 +31,12 @@ impl ProgressEvent {
             total: total
         }
     }
-    pub fn new_uninitialized(window: &Window) -> Root<ProgressEvent> {
+    pub fn new_uninitialized(global: &GlobalScope) -> Root<ProgressEvent> {
         reflect_dom_object(box ProgressEvent::new_inherited(false, 0, 0),
-                           GlobalRef::Window(window),
+                           global,
                            ProgressEventBinding::Wrap)
     }
-    pub fn new(global: GlobalRef, type_: Atom,
+    pub fn new(global: &GlobalScope, type_: Atom,
                can_bubble: EventBubbles, cancelable: EventCancelable,
                length_computable: bool, loaded: u64, total: u64) -> Root<ProgressEvent> {
         let ev = reflect_dom_object(box ProgressEvent::new_inherited(length_computable, loaded, total),
@@ -49,7 +48,7 @@ impl ProgressEvent {
         }
         ev
     }
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &ProgressEventBinding::ProgressEventInit)
                        -> Fallible<Root<ProgressEvent>> {
diff --git a/components/script/dom/promise.rs b/components/script/dom/promise.rs
index 5fd1ef6f85e..c0842dce4fa 100644
--- a/components/script/dom/promise.rs
+++ b/components/script/dom/promise.rs
@@ -15,9 +15,9 @@ use dom::bindings::callback::CallbackContainer;
 use dom::bindings::codegen::Bindings::PromiseBinding::AnyCallback;
 use dom::bindings::conversions::root_from_object;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::MutHeapJSVal;
 use dom::bindings::reflector::{Reflectable, MutReflectable, Reflector};
+use dom::globalscope::GlobalScope;
 use dom::promisenativehandler::PromiseNativeHandler;
 use js::conversions::ToJSValConvertible;
 use js::jsapi::{CallOriginalPromiseResolve, CallOriginalPromiseReject, CallOriginalPromiseThen};
@@ -61,7 +61,7 @@ impl PromiseHelper for Rc<Promise> {
 impl Drop for Promise {
     #[allow(unsafe_code)]
     fn drop(&mut self) {
-        let cx = self.global().r().get_cx();
+        let cx = self.global().get_cx();
         unsafe {
             RemoveRawValueRoot(cx, self.permanent_js_root.get_unsafe());
         }
@@ -70,7 +70,7 @@ impl Drop for Promise {
 
 impl Promise {
     #[allow(unsafe_code)]
-    pub fn new(global: GlobalRef) -> Rc<Promise> {
+    pub fn new(global: &GlobalScope) -> Rc<Promise> {
         let cx = global.get_cx();
         rooted!(in(cx) let mut obj = ptr::null_mut());
         unsafe {
@@ -81,7 +81,7 @@ impl Promise {
 
     #[allow(unsafe_code, unrooted_must_root)]
     pub fn duplicate(&self) -> Rc<Promise> {
-        let cx = self.global().r().get_cx();
+        let cx = self.global().get_cx();
         unsafe {
             Promise::new_with_js_promise(self.reflector().get_jsobject(), cx)
         }
@@ -112,7 +112,7 @@ impl Promise {
     }
 
     #[allow(unrooted_must_root, unsafe_code)]
-    pub fn Resolve(global: GlobalRef,
+    pub fn Resolve(global: &GlobalScope,
                    cx: *mut JSContext,
                    value: HandleValue) -> Fallible<Rc<Promise>> {
         let _ac = JSAutoCompartment::new(cx, global.reflector().get_jsobject().get());
@@ -124,7 +124,7 @@ impl Promise {
     }
 
     #[allow(unrooted_must_root, unsafe_code)]
-    pub fn Reject(global: GlobalRef,
+    pub fn Reject(global: &GlobalScope,
                   cx: *mut JSContext,
                   value: HandleValue) -> Fallible<Rc<Promise>> {
         let _ac = JSAutoCompartment::new(cx, global.reflector().get_jsobject().get());
@@ -166,7 +166,7 @@ impl Promise {
     pub fn reject_error(&self, cx: *mut JSContext, error: Error) {
         rooted!(in(cx) let mut v = UndefinedValue());
         unsafe {
-            error.to_jsval(cx, self.global().r(), v.handle_mut());
+            error.to_jsval(cx, &self.global(), v.handle_mut());
         }
         self.reject(cx, v.handle());
     }
@@ -210,8 +210,7 @@ impl Promise {
 
     #[allow(unsafe_code)]
     pub fn append_native_handler(&self, handler: &PromiseNativeHandler) {
-        let global = self.global();
-        let cx = global.r().get_cx();
+        let cx = self.global().get_cx();
         rooted!(in(cx) let resolve_func =
                 create_native_handler_function(cx,
                                                handler.reflector().get_jsobject(),
diff --git a/components/script/dom/promisenativehandler.rs b/components/script/dom/promisenativehandler.rs
index 603122556ef..b1c0ff3504c 100644
--- a/components/script/dom/promisenativehandler.rs
+++ b/components/script/dom/promisenativehandler.rs
@@ -3,10 +3,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::Bindings::PromiseNativeHandlerBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::trace::JSTraceable;
+use dom::globalscope::GlobalScope;
 use heapsize::HeapSizeOf;
 use js::jsapi::{JSContext, HandleValue};
 
@@ -22,7 +22,7 @@ pub struct PromiseNativeHandler {
 }
 
 impl PromiseNativeHandler {
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                resolve: Option<Box<Callback>>,
                reject: Option<Box<Callback>>)
                -> Root<PromiseNativeHandler> {
diff --git a/components/script/dom/radionodelist.rs b/components/script/dom/radionodelist.rs
index 9bbdae00c85..5cf05cb872a 100644
--- a/components/script/dom/radionodelist.rs
+++ b/components/script/dom/radionodelist.rs
@@ -6,7 +6,6 @@ use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementM
 use dom::bindings::codegen::Bindings::NodeListBinding::NodeListMethods;
 use dom::bindings::codegen::Bindings::RadioNodeListBinding;
 use dom::bindings::codegen::Bindings::RadioNodeListBinding::RadioNodeListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::reflect_dom_object;
@@ -32,7 +31,7 @@ impl RadioNodeList {
     #[allow(unrooted_must_root)]
     pub fn new(window: &Window, list_type: NodeListType) -> Root<RadioNodeList> {
         reflect_dom_object(box RadioNodeList::new_inherited(list_type),
-                           GlobalRef::Window(window),
+                           window,
                            RadioNodeListBinding::Wrap)
     }
 
diff --git a/components/script/dom/range.rs b/components/script/dom/range.rs
index bab6bdcc3a2..480740fa19f 100644
--- a/components/script/dom/range.rs
+++ b/components/script/dom/range.rs
@@ -11,7 +11,6 @@ use dom::bindings::codegen::Bindings::RangeBinding::RangeMethods;
 use dom::bindings::codegen::Bindings::TextBinding::TextMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::{CharacterDataTypeId, NodeTypeId};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutHeap, Root, RootedReference};
@@ -23,6 +22,7 @@ use dom::characterdata::CharacterData;
 use dom::document::Document;
 use dom::documentfragment::DocumentFragment;
 use dom::element::Element;
+use dom::globalscope::GlobalScope;
 use dom::htmlbodyelement::HTMLBodyElement;
 use dom::htmlscriptelement::HTMLScriptElement;
 use dom::node::{Node, UnbindContext};
@@ -60,7 +60,7 @@ impl Range {
                -> Root<Range> {
         let range = reflect_dom_object(box Range::new_inherited(start_container, start_offset,
                                                                 end_container, end_offset),
-                                       GlobalRef::Window(document.window()),
+                                       document.window(),
                                        RangeBinding::Wrap);
         start_container.ranges().push(WeakRef::new(&range));
         if start_container != end_container {
@@ -70,7 +70,7 @@ impl Range {
     }
 
     // https://dom.spec.whatwg.org/#dom-range
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<Range>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<Range>> {
         let document = global.as_window().Document();
         Ok(Range::new_with_doc(document.r()))
     }
diff --git a/components/script/dom/request.rs b/components/script/dom/request.rs
index fa665679c0d..efeafd5e289 100644
--- a/components/script/dom/request.rs
+++ b/components/script/dom/request.rs
@@ -17,10 +17,10 @@ use dom::bindings::codegen::Bindings::RequestBinding::RequestMode;
 use dom::bindings::codegen::Bindings::RequestBinding::RequestRedirect;
 use dom::bindings::codegen::Bindings::RequestBinding::RequestType;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, DOMString, USVString};
+use dom::globalscope::GlobalScope;
 use dom::headers::{Guard, Headers};
 use dom::promise::Promise;
 use dom::xmlhttprequest::Extractable;
@@ -51,7 +51,7 @@ pub struct Request {
 }
 
 impl Request {
-    fn new_inherited(global: GlobalRef,
+    fn new_inherited(global: &GlobalScope,
                      url: Url,
                      is_service_worker_global_scope: bool) -> Request {
         Request {
@@ -67,7 +67,7 @@ impl Request {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                url: Url,
                is_service_worker_global_scope: bool) -> Root<Request> {
         reflect_dom_object(box Request::new_inherited(global,
@@ -77,7 +77,7 @@ impl Request {
     }
 
     // https://fetch.spec.whatwg.org/#dom-request
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        input: RequestInfo,
                        init: &RequestInit)
                        -> Fallible<Root<Request>> {
@@ -130,7 +130,7 @@ impl Request {
 
         // Step 7
         // TODO: `entry settings object` is not implemented yet.
-        let origin = global.get_url().origin();
+        let origin = base_url.origin();
 
         // Step 8
         let mut window = Window::Client;
@@ -305,7 +305,7 @@ impl Request {
         let r = Request::from_net_request(global,
                                           false,
                                           request);
-        r.headers.or_init(|| Headers::for_request(r.global().r()));
+        r.headers.or_init(|| Headers::for_request(&r.global()));
 
         // Step 27
         let mut headers_copy = r.Headers();
@@ -412,7 +412,7 @@ impl Request {
 }
 
 impl Request {
-    fn from_net_request(global: GlobalRef,
+    fn from_net_request(global: &GlobalScope,
                         is_service_worker_global_scope: bool,
                         net_request: NetTraitsRequest) -> Root<Request> {
         let r = Request::new(global,
@@ -429,11 +429,7 @@ impl Request {
         let body_used = r.body_used.get();
         let mime_type = r.mime_type.borrow().clone();
         let headers_guard = r.Headers().get_guard();
-        let r_clone = reflect_dom_object(
-            box Request::new_inherited(r.global().r(),
-                                       url,
-                                       is_service_worker_global_scope),
-            r.global().r(), RequestBinding::Wrap);
+        let r_clone = Request::new(&r.global(), url, is_service_worker_global_scope);
         r_clone.request.borrow_mut().pipeline_id.set(req.pipeline_id.get());
         {
             let mut borrowed_r_request = r_clone.request.borrow_mut();
@@ -451,7 +447,7 @@ impl Request {
     }
 }
 
-fn net_request_from_global(global: GlobalRef,
+fn net_request_from_global(global: &GlobalScope,
                            url: Url,
                            is_service_worker_global_scope: bool) -> NetTraitsRequest {
     let origin = Origin::Origin(global.get_url().origin());
@@ -553,7 +549,7 @@ impl RequestMethods for Request {
 
     // https://fetch.spec.whatwg.org/#dom-request-headers
     fn Headers(&self) -> Root<Headers> {
-        self.headers.or_init(|| Headers::new(self.global().r()))
+        self.headers.or_init(|| Headers::new(&self.global()))
     }
 
     // https://fetch.spec.whatwg.org/#dom-request-type
diff --git a/components/script/dom/response.rs b/components/script/dom/response.rs
index 2287bb181b4..cabbd567b49 100644
--- a/components/script/dom/response.rs
+++ b/components/script/dom/response.rs
@@ -10,10 +10,10 @@ use dom::bindings::codegen::Bindings::ResponseBinding;
 use dom::bindings::codegen::Bindings::ResponseBinding::{ResponseMethods, ResponseType as DOMResponseType};
 use dom::bindings::codegen::Bindings::XMLHttpRequestBinding::BodyInit;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, USVString};
+use dom::globalscope::GlobalScope;
 use dom::headers::{Headers, Guard};
 use dom::headers::{is_vchar, is_obs_text};
 use dom::promise::Promise;
@@ -66,11 +66,11 @@ impl Response {
     }
 
     // https://fetch.spec.whatwg.org/#dom-response
-    pub fn new(global: GlobalRef) -> Root<Response> {
+    pub fn new(global: &GlobalScope) -> Root<Response> {
         reflect_dom_object(box Response::new_inherited(), global, ResponseBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef, body: Option<BodyInit>, init: &ResponseBinding::ResponseInit)
+    pub fn Constructor(global: &GlobalScope, body: Option<BodyInit>, init: &ResponseBinding::ResponseInit)
                        -> Fallible<Root<Response>> {
         // Step 1
         if init.status < 200 || init.status > 599 {
@@ -138,7 +138,7 @@ impl Response {
     }
 
     // https://fetch.spec.whatwg.org/#dom-response-error
-    pub fn Error(global: GlobalRef) -> Root<Response> {
+    pub fn Error(global: &GlobalScope) -> Root<Response> {
         let r = Response::new(global);
         *r.response_type.borrow_mut() = DOMResponseType::Error;
         r.Headers().set_guard(Guard::Immutable);
@@ -147,7 +147,7 @@ impl Response {
     }
 
     // https://fetch.spec.whatwg.org/#dom-response-redirect
-    pub fn Redirect(global: GlobalRef, url: USVString, status: u16) -> Fallible<Root<Response>> {
+    pub fn Redirect(global: &GlobalScope, url: USVString, status: u16) -> Fallible<Root<Response>> {
         // Step 1
         // TODO: `entry settings object` is not implemented in Servo yet.
         let base_url = global.get_url();
@@ -292,7 +292,7 @@ impl ResponseMethods for Response {
 
     // https://fetch.spec.whatwg.org/#dom-response-headers
     fn Headers(&self) -> Root<Headers> {
-        self.headers_reflector.or_init(|| Headers::for_response(self.global().r()))
+        self.headers_reflector.or_init(|| Headers::for_response(&self.global()))
     }
 
     // https://fetch.spec.whatwg.org/#dom-response-clone
@@ -301,7 +301,7 @@ impl ResponseMethods for Response {
         // TODO: This step relies on body and stream, which are still unimplemented.
 
         // Step 2
-        let new_response = Response::new(self.global().r());
+        let new_response = Response::new(&self.global());
         new_response.Headers().set_guard(self.Headers().get_guard());
 
         // https://fetch.spec.whatwg.org/#concept-response-clone
diff --git a/components/script/dom/screen.rs b/components/script/dom/screen.rs
index 158615e84dc..2c9fe185de1 100644
--- a/components/script/dom/screen.rs
+++ b/components/script/dom/screen.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::ScreenBinding;
 use dom::bindings::codegen::Bindings::ScreenBinding::ScreenMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::window::Window;
@@ -23,7 +22,7 @@ impl Screen {
 
     pub fn new(window: &Window) -> Root<Screen> {
         reflect_dom_object(box Screen::new_inherited(),
-                           GlobalRef::Window(window),
+                           window,
                            ScreenBinding::Wrap)
     }
 }
diff --git a/components/script/dom/serviceworker.rs b/components/script/dom/serviceworker.rs
index 8abcec513ce..8f3686f0b0c 100644
--- a/components/script/dom/serviceworker.rs
+++ b/components/script/dom/serviceworker.rs
@@ -7,7 +7,6 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::ServiceWorkerBinding::{ServiceWorkerMethods, ServiceWorkerState, Wrap};
 use dom::bindings::error::{ErrorResult, Error};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
@@ -15,6 +14,7 @@ use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::USVString;
 use dom::bindings::structuredclone::StructuredCloneData;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use js::jsapi::{HandleValue, JSContext};
 use script_thread::Runnable;
 use script_traits::{ScriptMsg, DOMMessage};
@@ -45,7 +45,7 @@ impl ServiceWorker {
         }
     }
 
-    pub fn install_serviceworker(global: GlobalRef,
+    pub fn install_serviceworker(global: &GlobalScope,
                 script_url: Url,
                 scope_url: Url,
                 skip_waiting: bool) -> Root<ServiceWorker> {
@@ -89,8 +89,10 @@ impl ServiceWorkerMethods for ServiceWorker {
         // Step 7
         let data = try!(StructuredCloneData::write(cx, message));
         let msg_vec = DOMMessage(data.move_to_arraybuffer());
-        let _ = self.global().r().constellation_chan().send(ScriptMsg::ForwardDOMMessage(msg_vec,
-                                                                                         self.scope_url.clone()));
+        let _ =
+            self.global()
+                .constellation_chan()
+                .send(ScriptMsg::ForwardDOMMessage(msg_vec, self.scope_url.clone()));
         Ok(())
     }
 
diff --git a/components/script/dom/serviceworkercontainer.rs b/components/script/dom/serviceworkercontainer.rs
index abeb69f2ea3..0947b9c0a1f 100644
--- a/components/script/dom/serviceworkercontainer.rs
+++ b/components/script/dom/serviceworkercontainer.rs
@@ -5,12 +5,12 @@
 use dom::bindings::codegen::Bindings::ServiceWorkerContainerBinding::{ServiceWorkerContainerMethods, Wrap};
 use dom::bindings::codegen::Bindings::ServiceWorkerContainerBinding::RegistrationOptions;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::USVString;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::serviceworker::ServiceWorker;
 use dom::serviceworkerregistration::ServiceWorkerRegistration;
 use script_thread::ScriptThread;
@@ -31,7 +31,7 @@ impl ServiceWorkerContainer {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<ServiceWorkerContainer> {
+    pub fn new(global: &GlobalScope) -> Root<ServiceWorkerContainer> {
         reflect_dom_object(box ServiceWorkerContainer::new_inherited(), global, Wrap)
     }
 }
@@ -58,8 +58,9 @@ impl ServiceWorkerContainerMethods for ServiceWorkerContainer {
                 script_url: USVString,
                 options: &RegistrationOptions) -> Fallible<Root<ServiceWorkerRegistration>> {
         let USVString(ref script_url) = script_url;
+        let api_base_url = self.global().api_base_url();
         // Step 3-4
-        let script_url = match self.global().r().api_base_url().join(script_url) {
+        let script_url = match api_base_url.join(script_url) {
             Ok(url) => url,
             Err(_) => return Err(Error::Type("Invalid script URL".to_owned()))
         };
@@ -77,7 +78,7 @@ impl ServiceWorkerContainerMethods for ServiceWorkerContainer {
         let scope = match options.scope {
             Some(ref scope) => {
                 let &USVString(ref inner_scope) = scope;
-                match self.global().r().api_base_url().join(inner_scope) {
+                match api_base_url.join(inner_scope) {
                     Ok(url) => url,
                     Err(_) => return Err(Error::Type("Invalid scope URL".to_owned()))
                 }
@@ -95,11 +96,12 @@ impl ServiceWorkerContainerMethods for ServiceWorkerContainer {
             return Err(Error::Type("Scope URL contains forbidden characters".to_owned()));
         }
 
-        let worker_registration = ServiceWorkerRegistration::new(self.global().r(),
+        let global = self.global();
+        let worker_registration = ServiceWorkerRegistration::new(&global,
                                                                  script_url,
                                                                  scope.clone(),
                                                                  self);
-        ScriptThread::set_registration(scope, &*worker_registration, self.global().r().pipeline_id());
+        ScriptThread::set_registration(scope, &*worker_registration, global.pipeline_id());
         Ok(worker_registration)
     }
 }
diff --git a/components/script/dom/serviceworkerglobalscope.rs b/components/script/dom/serviceworkerglobalscope.rs
index 6efd555c909..10d01d4b41a 100644
--- a/components/script/dom/serviceworkerglobalscope.rs
+++ b/components/script/dom/serviceworkerglobalscope.rs
@@ -8,7 +8,6 @@ use dom::abstractworker::WorkerScriptMsg;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::ServiceWorkerGlobalScopeBinding;
 use dom::bindings::codegen::Bindings::ServiceWorkerGlobalScopeBinding::ServiceWorkerGlobalScopeMethods;
-use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, RootCollection};
 use dom::bindings::reflector::Reflectable;
@@ -17,6 +16,7 @@ use dom::event::Event;
 use dom::eventtarget::EventTarget;
 use dom::extendableevent::ExtendableEvent;
 use dom::extendablemessageevent::ExtendableMessageEvent;
+use dom::globalscope::GlobalScope;
 use dom::workerglobalscope::WorkerGlobalScope;
 use ipc_channel::ipc::{self, IpcSender, IpcReceiver};
 use ipc_channel::router::ROUTER;
@@ -192,7 +192,7 @@ impl ServiceWorkerGlobalScope {
 
             global.dispatch_activate();
             let reporter_name = format!("service-worker-reporter-{}", random::<u64>());
-            scope.mem_profiler_chan().run_with_memory_reporting(|| {
+            scope.upcast::<GlobalScope>().mem_profiler_chan().run_with_memory_reporting(|| {
                 while let Ok(event) = global.receive_event() {
                     if !global.handle_event(event) {
                         break;
@@ -205,14 +205,13 @@ impl ServiceWorkerGlobalScope {
     fn handle_event(&self, event: MixedMessage) -> bool {
         match event {
             MixedMessage::FromDevtools(msg) => {
-                let global_ref = GlobalRef::Worker(self.upcast());
                 match msg {
                     DevtoolScriptControlMsg::EvaluateJS(_pipe_id, string, sender) =>
-                        devtools::handle_evaluate_js(&global_ref, string, sender),
+                        devtools::handle_evaluate_js(self.upcast(), string, sender),
                     DevtoolScriptControlMsg::GetCachedMessages(pipe_id, message_types, sender) =>
                         devtools::handle_get_cached_messages(pipe_id, message_types, sender),
                     DevtoolScriptControlMsg::WantsLiveNotifications(_pipe_id, bool_val) =>
-                        devtools::handle_wants_live_notifications(&global_ref, bool_val),
+                        devtools::handle_wants_live_notifications(self.upcast(), bool_val),
                     _ => debug!("got an unusable devtools control message inside the worker!"),
                 }
                 true
@@ -237,8 +236,8 @@ impl ServiceWorkerGlobalScope {
                 let target = self.upcast();
                 let _ac = JSAutoCompartment::new(scope.get_cx(), scope.reflector().get_jsobject().get());
                 rooted!(in(scope.get_cx()) let mut message = UndefinedValue());
-                data.read(GlobalRef::Worker(scope), message.handle_mut());
-                ExtendableMessageEvent::dispatch_jsval(target, GlobalRef::Worker(scope), message.handle());
+                data.read(scope.upcast(), message.handle_mut());
+                ExtendableMessageEvent::dispatch_jsval(target, scope.upcast(), message.handle());
             },
             CommonWorker(WorkerScriptMsg::Common(CommonScriptMsg::RunnableMsg(_, runnable))) => {
                 runnable.handler()
@@ -302,8 +301,7 @@ impl ServiceWorkerGlobalScope {
     }
 
     fn dispatch_activate(&self) {
-        let global = GlobalRef::Worker(self.upcast::<WorkerGlobalScope>());
-        let event = ExtendableEvent::new(global, atom!("activate"), false, false);
+        let event = ExtendableEvent::new(self.upcast(), atom!("activate"), false, false);
         let event = (&*event).upcast::<Event>();
         self.upcast::<EventTarget>().dispatch_event(event);
     }
@@ -311,11 +309,9 @@ impl ServiceWorkerGlobalScope {
 
 #[allow(unsafe_code)]
 unsafe extern "C" fn interrupt_callback(cx: *mut JSContext) -> bool {
-    let global = global_root_from_context(cx);
-    let worker = match global.r() {
-        GlobalRef::Worker(w) => w,
-        _ => panic!("global for worker is not a worker scope")
-    };
+    let worker =
+        Root::downcast::<WorkerGlobalScope>(GlobalScope::from_context(cx))
+            .expect("global is not a worker scope");
     assert!(worker.is::<ServiceWorkerGlobalScope>());
 
     // A false response causes the script to terminate
diff --git a/components/script/dom/serviceworkerregistration.rs b/components/script/dom/serviceworkerregistration.rs
index f7c47b8ecec..c3a08e514e4 100644
--- a/components/script/dom/serviceworkerregistration.rs
+++ b/components/script/dom/serviceworkerregistration.rs
@@ -4,11 +4,11 @@
 
 use dom::bindings::codegen::Bindings::ServiceWorkerBinding::ServiceWorkerState;
 use dom::bindings::codegen::Bindings::ServiceWorkerRegistrationBinding::{ServiceWorkerRegistrationMethods, Wrap};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::USVString;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::serviceworker::ServiceWorker;
 use dom::serviceworkercontainer::Controllable;
 use dom::workerglobalscope::prepare_workerscope_init;
@@ -35,7 +35,7 @@ impl ServiceWorkerRegistration {
         }
     }
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                script_url: Url,
                scope: Url,
                container: &Controllable) -> Root<ServiceWorkerRegistration> {
@@ -49,7 +49,7 @@ impl ServiceWorkerRegistration {
         self.active.as_ref().unwrap()
     }
 
-    pub fn create_scope_things(global: GlobalRef, script_url: Url) -> ScopeThings {
+    pub fn create_scope_things(global: &GlobalScope, script_url: Url) -> ScopeThings {
         let worker_load_origin = WorkerScriptLoadOrigin {
             referrer_url: None,
             referrer_policy: None,
@@ -57,12 +57,13 @@ impl ServiceWorkerRegistration {
         };
 
         let worker_id = global.get_next_worker_id();
+        let devtools_chan = global.devtools_chan().cloned();
         let init = prepare_workerscope_init(global, None);
         ScopeThings {
             script_url: script_url,
             init: init,
             worker_load_origin: worker_load_origin,
-            devtools_chan: global.devtools_chan(),
+            devtools_chan: devtools_chan,
             worker_id: worker_id
         }
     }
diff --git a/components/script/dom/servohtmlparser.rs b/components/script/dom/servohtmlparser.rs
index 24a22be75dd..a65d9e84a6d 100644
--- a/components/script/dom/servohtmlparser.rs
+++ b/components/script/dom/servohtmlparser.rs
@@ -11,13 +11,14 @@ use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::HTMLImageElementBinding::HTMLImageElementMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::ServoHTMLParserBinding;
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::bindings::trace::JSTraceable;
 use dom::document::Document;
+use dom::globalscope::GlobalScope;
 use dom::htmlimageelement::HTMLImageElement;
 use dom::node::Node;
 use dom::window::Window;
@@ -277,8 +278,7 @@ impl ServoHTMLParser {
             pipeline: pipeline,
         };
 
-        reflect_dom_object(box parser, GlobalRef::Window(document.window()),
-                           ServoHTMLParserBinding::Wrap)
+        reflect_dom_object(box parser, document.window(), ServoHTMLParserBinding::Wrap)
     }
 
     #[allow(unrooted_must_root)]
@@ -314,8 +314,7 @@ impl ServoHTMLParser {
             pipeline: None,
         };
 
-        reflect_dom_object(box parser, GlobalRef::Window(document.window()),
-                           ServoHTMLParserBinding::Wrap)
+        reflect_dom_object(box parser, document.window(), ServoHTMLParserBinding::Wrap)
     }
 
     #[inline]
@@ -346,7 +345,7 @@ impl ServoHTMLParser {
         };
         profile(ProfilerCategory::ScriptParseHTML,
                 Some(metadata),
-                self.document.window().time_profiler_chan().clone(),
+                self.document.window().upcast::<GlobalScope>().time_profiler_chan().clone(),
                 || self.do_parse_sync())
     }
 
diff --git a/components/script/dom/servoxmlparser.rs b/components/script/dom/servoxmlparser.rs
index 892477ffd0f..2b79a5cf117 100644
--- a/components/script/dom/servoxmlparser.rs
+++ b/components/script/dom/servoxmlparser.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::ServoXMLParserBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::trace::JSTraceable;
@@ -95,8 +94,7 @@ impl ServoXMLParser {
             pipeline: pipeline,
         };
 
-        reflect_dom_object(box parser, GlobalRef::Window(document.window()),
-                           ServoXMLParserBinding::Wrap)
+        reflect_dom_object(box parser, document.window(), ServoXMLParserBinding::Wrap)
     }
 
     pub fn window(&self) -> &Window {
diff --git a/components/script/dom/storage.rs b/components/script/dom/storage.rs
index 411e304b2f5..b8a3865cadd 100644
--- a/components/script/dom/storage.rs
+++ b/components/script/dom/storage.rs
@@ -5,13 +5,13 @@
 use dom::bindings::codegen::Bindings::StorageBinding;
 use dom::bindings::codegen::Bindings::StorageBinding::StorageMethods;
 use dom::bindings::error::{Error, ErrorResult};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::storageevent::StorageEvent;
 use dom::urlhelper::UrlHelper;
 use ipc_channel::ipc::{self, IpcSender};
@@ -35,20 +35,16 @@ impl Storage {
         }
     }
 
-    pub fn new(global: &GlobalRef, storage_type: StorageType) -> Root<Storage> {
-        reflect_dom_object(box Storage::new_inherited(storage_type), *global, StorageBinding::Wrap)
+    pub fn new(global: &GlobalScope, storage_type: StorageType) -> Root<Storage> {
+        reflect_dom_object(box Storage::new_inherited(storage_type), global, StorageBinding::Wrap)
     }
 
     fn get_url(&self) -> Url {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.get_url()
+        self.global().get_url()
     }
 
     fn get_storage_thread(&self) -> IpcSender<StorageThreadMsg> {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        global_ref.as_window().resource_threads().sender()
+        self.global().resource_threads().sender()
     }
 
 }
@@ -154,13 +150,14 @@ impl Storage {
     /// https://html.spec.whatwg.org/multipage/#send-a-storage-notification
     fn broadcast_change_notification(&self, key: Option<String>, old_value: Option<String>,
                                      new_value: Option<String>) {
-        let global_root = self.global();
-        let global_ref = global_root.r();
-        let window = global_ref.as_window();
+        let global = self.global();
+        let window = global.as_window();
         let task_source = window.dom_manipulation_task_source();
         let trusted_storage = Trusted::new(self);
-        task_source.queue(box StorageEventRunnable::new(trusted_storage, key, old_value, new_value),
-                          global_ref).unwrap();
+        task_source
+            .queue(
+                box StorageEventRunnable::new(trusted_storage, key, old_value, new_value), &global)
+            .unwrap();
     }
 }
 
@@ -185,13 +182,11 @@ impl Runnable for StorageEventRunnable {
         let this = *self;
         let storage_root = this.element.root();
         let storage = storage_root.r();
-        let global_root = storage.global();
-        let global_ref = global_root.r();
-        let ev_window = global_ref.as_window();
+        let global = storage.global();
         let ev_url = storage.get_url();
 
         let storage_event = StorageEvent::new(
-            global_ref,
+            &global,
             atom!("storage"),
             EventBubbles::DoesNotBubble, EventCancelable::NotCancelable,
             this.key.map(DOMString::from), this.old_value.map(DOMString::from), this.new_value.map(DOMString::from),
@@ -206,7 +201,7 @@ impl Runnable for StorageEventRunnable {
             assert!(UrlHelper::SameOrigin(&ev_url, &it_window.get_url()));
             // TODO: Such a Document object is not necessarily fully active, but events fired on such
             // objects are ignored by the event loop until the Document becomes fully active again.
-            if ev_window.pipeline_id() != it_window.pipeline_id() {
+            if global.pipeline_id() != it_window.upcast::<GlobalScope>().pipeline_id() {
                 storage_event.upcast::<Event>().fire(it_window.upcast());
             }
         }
diff --git a/components/script/dom/storageevent.rs b/components/script/dom/storageevent.rs
index 69fe7c257d5..21c16f1db78 100644
--- a/components/script/dom/storageevent.rs
+++ b/components/script/dom/storageevent.rs
@@ -6,12 +6,12 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::StorageEventBinding;
 use dom::bindings::codegen::Bindings::StorageEventBinding::StorageEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::storage::Storage;
 use dom::window::Window;
 use string_cache::Atom;
@@ -46,11 +46,11 @@ impl StorageEvent {
     pub fn new_uninitialized(window: &Window,
                              url: DOMString) -> Root<StorageEvent> {
         reflect_dom_object(box StorageEvent::new_inherited(None, None, None, url, None),
-                           GlobalRef::Window(window),
+                           window,
                            StorageEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable,
@@ -70,7 +70,7 @@ impl StorageEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &StorageEventBinding::StorageEventInit) -> Fallible<Root<StorageEvent>> {
         let key = init.key.clone();
diff --git a/components/script/dom/stylesheet.rs b/components/script/dom/stylesheet.rs
index 15b8693c537..02c96623800 100644
--- a/components/script/dom/stylesheet.rs
+++ b/components/script/dom/stylesheet.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::StyleSheetBinding;
 use dom::bindings::codegen::Bindings::StyleSheetBinding::StyleSheetMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -35,7 +34,7 @@ impl StyleSheet {
                href: Option<DOMString>,
                title: Option<DOMString>) -> Root<StyleSheet> {
         reflect_dom_object(box StyleSheet::new_inherited(type_, href, title),
-                           GlobalRef::Window(window),
+                           window,
                            StyleSheetBinding::Wrap)
     }
 }
diff --git a/components/script/dom/stylesheetlist.rs b/components/script/dom/stylesheetlist.rs
index 721ac06525c..a4541fc9bb4 100644
--- a/components/script/dom/stylesheetlist.rs
+++ b/components/script/dom/stylesheetlist.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::StyleSheetListBinding;
 use dom::bindings::codegen::Bindings::StyleSheetListBinding::StyleSheetListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::document::Document;
@@ -29,7 +28,7 @@ impl StyleSheetList {
     #[allow(unrooted_must_root)]
     pub fn new(window: &Window, document: JS<Document>) -> Root<StyleSheetList> {
         reflect_dom_object(box StyleSheetList::new_inherited(document),
-                           GlobalRef::Window(window), StyleSheetListBinding::Wrap)
+                           window, StyleSheetListBinding::Wrap)
     }
 }
 
diff --git a/components/script/dom/testbinding.rs b/components/script/dom/testbinding.rs
index 6f7d7baf770..fe76ddccab9 100644
--- a/components/script/dom/testbinding.rs
+++ b/components/script/dom/testbinding.rs
@@ -21,7 +21,6 @@ use dom::bindings::codegen::UnionTypes::{HTMLElementOrUnsignedLongOrStringOrBool
 use dom::bindings::codegen::UnionTypes::{StringOrLongSequence, StringOrStringSequence, StringSequenceOrUnsignedLong};
 use dom::bindings::codegen::UnionTypes::{StringOrUnsignedLong, StringOrBoolean, UnsignedLongOrBoolean};
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::js::Root;
 use dom::bindings::mozmap::MozMap;
 use dom::bindings::num::Finite;
@@ -30,6 +29,7 @@ use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{ByteString, DOMString, USVString};
 use dom::bindings::weakref::MutableWeakRef;
 use dom::blob::{Blob, BlobImpl};
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use dom::promisenativehandler::{PromiseNativeHandler, Callback};
 use dom::url::URL;
@@ -57,22 +57,22 @@ impl TestBinding {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<TestBinding> {
+    pub fn new(global: &GlobalScope) -> Root<TestBinding> {
         reflect_dom_object(box TestBinding::new_inherited(),
                            global, TestBindingBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<TestBinding>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<TestBinding>> {
         Ok(TestBinding::new(global))
     }
 
     #[allow(unused_variables)]
-    pub fn Constructor_(global: GlobalRef, nums: Vec<f64>) -> Fallible<Root<TestBinding>> {
+    pub fn Constructor_(global: &GlobalScope, nums: Vec<f64>) -> Fallible<Root<TestBinding>> {
         Ok(TestBinding::new(global))
     }
 
     #[allow(unused_variables)]
-    pub fn Constructor__(global: GlobalRef, num: f64) -> Fallible<Root<TestBinding>> {
+    pub fn Constructor__(global: &GlobalScope, num: f64) -> Fallible<Root<TestBinding>> {
         Ok(TestBinding::new(global))
     }
 }
@@ -113,7 +113,7 @@ impl TestBindingMethods for TestBinding {
     fn EnumAttribute(&self) -> TestEnum { TestEnum::_empty }
     fn SetEnumAttribute(&self, _: TestEnum) {}
     fn InterfaceAttribute(&self) -> Root<Blob> {
-        Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
+        Blob::new(&self.global(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
     }
     fn SetInterfaceAttribute(&self, _: &Blob) {}
     fn UnionAttribute(&self) -> HTMLElementOrLong { HTMLElementOrLong::Long(0) }
@@ -209,7 +209,7 @@ impl TestBindingMethods for TestBinding {
     fn SetAttr_to_automatically_rename(&self, _: DOMString) {}
     fn GetEnumAttributeNullable(&self) -> Option<TestEnum> { Some(TestEnum::_empty) }
     fn GetInterfaceAttributeNullable(&self) -> Option<Root<Blob>> {
-        Some(Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
+        Some(Blob::new(&self.global(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
     }
     fn SetInterfaceAttributeNullable(&self, _: Option<&Blob>) {}
     fn GetInterfaceAttributeWeak(&self) -> Option<Root<URL>> {
@@ -264,7 +264,7 @@ impl TestBindingMethods for TestBinding {
     fn ReceiveByteString(&self) -> ByteString { ByteString::new(vec!()) }
     fn ReceiveEnum(&self) -> TestEnum { TestEnum::_empty }
     fn ReceiveInterface(&self) -> Root<Blob> {
-        Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
+        Blob::new(&self.global(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
     }
     fn ReceiveAny(&self, _: *mut JSContext) -> JSVal { NullValue() }
     fn ReceiveObject(&self, cx: *mut JSContext) -> NonZero<*mut JSObject> {
@@ -287,7 +287,7 @@ impl TestBindingMethods for TestBinding {
     }
     fn ReceiveSequence(&self) -> Vec<i32> { vec![1] }
     fn ReceiveInterfaceSequence(&self) -> Vec<Root<Blob>> {
-        vec![Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())]
+        vec![Blob::new(&self.global(), BlobImpl::new_from_bytes(vec![]), "".to_owned())]
     }
 
     fn ReceiveNullableBoolean(&self) -> Option<bool> { Some(false) }
@@ -308,7 +308,7 @@ impl TestBindingMethods for TestBinding {
     fn ReceiveNullableByteString(&self) -> Option<ByteString> { Some(ByteString::new(vec!())) }
     fn ReceiveNullableEnum(&self) -> Option<TestEnum> { Some(TestEnum::_empty) }
     fn ReceiveNullableInterface(&self) -> Option<Root<Blob>> {
-        Some(Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
+        Some(Blob::new(&self.global(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
     }
     fn ReceiveNullableObject(&self, cx: *mut JSContext) -> Option<NonZero<*mut JSObject>> {
         self.GetObjectAttributeNullable(cx)
@@ -655,12 +655,12 @@ impl TestBindingMethods for TestBinding {
 
     #[allow(unrooted_must_root)]
     fn ReturnResolvedPromise(&self, cx: *mut JSContext, v: HandleValue) -> Fallible<Rc<Promise>> {
-        Promise::Resolve(self.global().r(), cx, v)
+        Promise::Resolve(&self.global(), cx, v)
     }
 
     #[allow(unrooted_must_root)]
     fn ReturnRejectedPromise(&self, cx: *mut JSContext, v: HandleValue) -> Fallible<Rc<Promise>> {
-        Promise::Reject(self.global().r(), cx, v)
+        Promise::Reject(&self.global(), cx, v)
     }
 
     fn PromiseResolveNative(&self, cx: *mut JSContext, p: &Promise, v: HandleValue) {
@@ -672,7 +672,7 @@ impl TestBindingMethods for TestBinding {
     }
 
     fn PromiseRejectWithTypeError(&self, p: &Promise, s: USVString) {
-        p.reject_error(self.global().r().get_cx(), Error::Type(s.0));
+        p.reject_error(self.global().get_cx(), Error::Type(s.0));
     }
 
     #[allow(unrooted_must_root)]
@@ -682,8 +682,10 @@ impl TestBindingMethods for TestBinding {
             promise: TrustedPromise::new(promise),
             value: value,
         };
-        let _ = self.global().r().schedule_callback(OneshotTimerCallback::TestBindingCallback(cb),
-                                                    MsDuration::new(delay));
+        let _ = self.global()
+            .schedule_callback(
+                OneshotTimerCallback::TestBindingCallback(cb),
+                MsDuration::new(delay));
     }
 
     #[allow(unrooted_must_root)]
@@ -691,10 +693,10 @@ impl TestBindingMethods for TestBinding {
                             resolve: Option<Rc<SimpleCallback>>,
                             reject: Option<Rc<SimpleCallback>>) -> Rc<Promise> {
         let global = self.global();
-        let handler = PromiseNativeHandler::new(global.r(),
+        let handler = PromiseNativeHandler::new(&global,
                                                 resolve.map(SimpleHandler::new),
                                                 reject.map(SimpleHandler::new));
-        let p = Promise::new(global.r());
+        let p = Promise::new(&global);
         p.append_native_handler(&handler);
         return p;
 
@@ -711,15 +713,15 @@ impl TestBindingMethods for TestBinding {
         impl Callback for SimpleHandler {
             #[allow(unsafe_code)]
             fn callback(&self, cx: *mut JSContext, v: HandleValue) {
-                let global = unsafe { global_root_from_context(cx) };
-                let _ = self.handler.Call_(&global.r(), v, ExceptionHandling::Report);
+                let global = unsafe { GlobalScope::from_context(cx) };
+                let _ = self.handler.Call_(&*global, v, ExceptionHandling::Report);
             }
         }
     }
 
     #[allow(unrooted_must_root)]
     fn PromiseAttribute(&self) -> Rc<Promise> {
-        Promise::new(self.global().r())
+        Promise::new(&self.global())
     }
 
     fn AcceptPromise(&self, _promise: &Promise) {
@@ -749,24 +751,24 @@ impl TestBindingMethods for TestBinding {
     }
 
     fn AdvanceClock(&self, ms: i32, tick: bool) {
-        self.global().r().as_window().advance_animation_clock(ms, tick);
+        self.global().as_window().advance_animation_clock(ms, tick);
     }
 
     fn Panic(&self) { panic!("explicit panic from script") }
 }
 
 impl TestBinding {
-    pub fn BooleanAttributeStatic(_: GlobalRef) -> bool { false }
-    pub fn SetBooleanAttributeStatic(_: GlobalRef, _: bool) {}
-    pub fn ReceiveVoidStatic(_: GlobalRef) {}
-    pub fn PrefControlledStaticAttributeDisabled(_: GlobalRef) -> bool { false }
-    pub fn PrefControlledStaticAttributeEnabled(_: GlobalRef) -> bool { false }
-    pub fn PrefControlledStaticMethodDisabled(_: GlobalRef) {}
-    pub fn PrefControlledStaticMethodEnabled(_: GlobalRef) {}
-    pub fn FuncControlledStaticAttributeDisabled(_: GlobalRef) -> bool { false }
-    pub fn FuncControlledStaticAttributeEnabled(_: GlobalRef) -> bool { false }
-    pub fn FuncControlledStaticMethodDisabled(_: GlobalRef) {}
-    pub fn FuncControlledStaticMethodEnabled(_: GlobalRef) {}
+    pub fn BooleanAttributeStatic(_: &GlobalScope) -> bool { false }
+    pub fn SetBooleanAttributeStatic(_: &GlobalScope, _: bool) {}
+    pub fn ReceiveVoidStatic(_: &GlobalScope) {}
+    pub fn PrefControlledStaticAttributeDisabled(_: &GlobalScope) -> bool { false }
+    pub fn PrefControlledStaticAttributeEnabled(_: &GlobalScope) -> bool { false }
+    pub fn PrefControlledStaticMethodDisabled(_: &GlobalScope) {}
+    pub fn PrefControlledStaticMethodEnabled(_: &GlobalScope) {}
+    pub fn FuncControlledStaticAttributeDisabled(_: &GlobalScope) -> bool { false }
+    pub fn FuncControlledStaticAttributeEnabled(_: &GlobalScope) -> bool { false }
+    pub fn FuncControlledStaticMethodDisabled(_: &GlobalScope) {}
+    pub fn FuncControlledStaticMethodEnabled(_: &GlobalScope) {}
 }
 
 #[allow(unsafe_code)]
@@ -786,7 +788,7 @@ impl TestBindingCallback {
     #[allow(unrooted_must_root)]
     pub fn invoke(self) {
         let p = self.promise.root();
-        let cx = p.global().r().get_cx();
+        let cx = p.global().get_cx();
         let _ac = JSAutoCompartment::new(cx, p.reflector().get_jsobject().get());
         p.resolve_native(cx, &self.value);
     }
diff --git a/components/script/dom/testbindingiterable.rs b/components/script/dom/testbindingiterable.rs
index 2ad0df6dbb6..10045705192 100644
--- a/components/script/dom/testbindingiterable.rs
+++ b/components/script/dom/testbindingiterable.rs
@@ -7,10 +7,10 @@
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::TestBindingIterableBinding::{self, TestBindingIterableMethods};
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct TestBindingIterable {
@@ -19,14 +19,14 @@ pub struct TestBindingIterable {
 }
 
 impl TestBindingIterable {
-    fn new(global: GlobalRef) -> Root<TestBindingIterable> {
+    fn new(global: &GlobalScope) -> Root<TestBindingIterable> {
         reflect_dom_object(box TestBindingIterable {
             reflector: Reflector::new(),
             vals: DOMRefCell::new(vec![]),
         }, global, TestBindingIterableBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<TestBindingIterable>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<TestBindingIterable>> {
         Ok(TestBindingIterable::new(global))
     }
 }
diff --git a/components/script/dom/testbindingpairiterable.rs b/components/script/dom/testbindingpairiterable.rs
index 9bceedd4980..f536459c1e9 100644
--- a/components/script/dom/testbindingpairiterable.rs
+++ b/components/script/dom/testbindingpairiterable.rs
@@ -8,11 +8,11 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::TestBindingPairIterableBinding;
 use dom::bindings::codegen::Bindings::TestBindingPairIterableBinding::TestBindingPairIterableMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::iterable::Iterable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct TestBindingPairIterable {
@@ -35,14 +35,14 @@ impl Iterable for TestBindingPairIterable {
 }
 
 impl TestBindingPairIterable {
-    fn new(global: GlobalRef) -> Root<TestBindingPairIterable> {
+    fn new(global: &GlobalScope) -> Root<TestBindingPairIterable> {
         reflect_dom_object(box TestBindingPairIterable {
             reflector: Reflector::new(),
             map: DOMRefCell::new(vec![]),
         }, global, TestBindingPairIterableBinding::TestBindingPairIterableWrap)
     }
 
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<TestBindingPairIterable>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<TestBindingPairIterable>> {
         Ok(TestBindingPairIterable::new(global))
     }
 }
diff --git a/components/script/dom/text.rs b/components/script/dom/text.rs
index 5d377e1e05d..914d415dc0a 100644
--- a/components/script/dom/text.rs
+++ b/components/script/dom/text.rs
@@ -8,13 +8,13 @@ use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::TextBinding::{self, TextMethods};
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::js::RootedReference;
 use dom::bindings::str::DOMString;
 use dom::characterdata::CharacterData;
 use dom::document::Document;
+use dom::globalscope::GlobalScope;
 use dom::node::Node;
 
 /// An HTML text node.
@@ -35,7 +35,7 @@ impl Text {
                            document, TextBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef, text: DOMString) -> Fallible<Root<Text>> {
+    pub fn Constructor(global: &GlobalScope, text: DOMString) -> Fallible<Root<Text>> {
         let document = global.as_window().Document();
         Ok(Text::new(text, document.r()))
     }
diff --git a/components/script/dom/textdecoder.rs b/components/script/dom/textdecoder.rs
index fae78342a73..db18d9a5be4 100644
--- a/components/script/dom/textdecoder.rs
+++ b/components/script/dom/textdecoder.rs
@@ -6,10 +6,10 @@ use dom::bindings::codegen::Bindings::TextDecoderBinding;
 use dom::bindings::codegen::Bindings::TextDecoderBinding::TextDecoderMethods;
 use dom::bindings::conversions::array_buffer_view_data;
 use dom::bindings::error::{Error, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
+use dom::globalscope::GlobalScope;
 use encoding::label::encoding_from_whatwg_label;
 use encoding::types::{DecoderTrap, EncodingRef};
 use js::jsapi::{JSContext, JSObject};
@@ -36,14 +36,14 @@ impl TextDecoder {
         Err(Error::Range("The given encoding is not supported.".to_owned()))
     }
 
-    pub fn new(global: GlobalRef, encoding: EncodingRef, fatal: bool) -> Root<TextDecoder> {
+    pub fn new(global: &GlobalScope, encoding: EncodingRef, fatal: bool) -> Root<TextDecoder> {
         reflect_dom_object(box TextDecoder::new_inherited(encoding, fatal),
                            global,
                            TextDecoderBinding::Wrap)
     }
 
     /// https://encoding.spec.whatwg.org/#dom-textdecoder
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        label: DOMString,
                        options: &TextDecoderBinding::TextDecoderOptions)
                             -> Fallible<Root<TextDecoder>> {
diff --git a/components/script/dom/textencoder.rs b/components/script/dom/textencoder.rs
index 996e5d28e98..9c8ad647080 100644
--- a/components/script/dom/textencoder.rs
+++ b/components/script/dom/textencoder.rs
@@ -6,10 +6,10 @@ use core::nonzero::NonZero;
 use dom::bindings::codegen::Bindings::TextEncoderBinding;
 use dom::bindings::codegen::Bindings::TextEncoderBinding::TextEncoderMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
+use dom::globalscope::GlobalScope;
 use encoding::EncoderTrap;
 use encoding::Encoding;
 use encoding::all::UTF_8;
@@ -30,14 +30,14 @@ impl TextEncoder {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<TextEncoder> {
+    pub fn new(global: &GlobalScope) -> Root<TextEncoder> {
         reflect_dom_object(box TextEncoder::new_inherited(),
                            global,
                            TextEncoderBinding::Wrap)
     }
 
     // https://encoding.spec.whatwg.org/#dom-textencoder
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<TextEncoder>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<TextEncoder>> {
         Ok(TextEncoder::new(global))
     }
 }
diff --git a/components/script/dom/touch.rs b/components/script/dom/touch.rs
index 29bfac34152..32eeb24b6e1 100644
--- a/components/script/dom/touch.rs
+++ b/components/script/dom/touch.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::TouchBinding;
 use dom::bindings::codegen::Bindings::TouchBinding::TouchMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::num::Finite;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -50,7 +49,8 @@ impl Touch {
                                                     screen_x, screen_y,
                                                     client_x, client_y,
                                                     page_x, page_y),
-                           GlobalRef::Window(window), TouchBinding::Wrap)
+                           window,
+                           TouchBinding::Wrap)
     }
 }
 
diff --git a/components/script/dom/touchevent.rs b/components/script/dom/touchevent.rs
index 1a2f7334cdf..9b4b3a250d5 100644
--- a/components/script/dom/touchevent.rs
+++ b/components/script/dom/touchevent.rs
@@ -5,7 +5,6 @@
 use dom::bindings::codegen::Bindings::TouchEventBinding;
 use dom::bindings::codegen::Bindings::TouchEventBinding::TouchEventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutHeap, Root};
 use dom::bindings::reflector::reflect_dom_object;
@@ -49,7 +48,7 @@ impl TouchEvent {
                      changed_touches: &TouchList,
                      target_touches: &TouchList) -> Root<TouchEvent> {
         reflect_dom_object(box TouchEvent::new_inherited(touches, changed_touches, target_touches),
-                           GlobalRef::Window(window),
+                           window,
                            TouchEventBinding::Wrap)
     }
 
diff --git a/components/script/dom/touchlist.rs b/components/script/dom/touchlist.rs
index 14bb8a68766..a4ff7f8443e 100644
--- a/components/script/dom/touchlist.rs
+++ b/components/script/dom/touchlist.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::TouchListBinding;
 use dom::bindings::codegen::Bindings::TouchListBinding::TouchListMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::touch::Touch;
@@ -26,7 +25,7 @@ impl TouchList {
 
     pub fn new(window: &Window, touches: &[&Touch]) -> Root<TouchList> {
         reflect_dom_object(box TouchList::new_inherited(touches),
-                           GlobalRef::Window(window), TouchListBinding::Wrap)
+                           window, TouchListBinding::Wrap)
     }
 }
 
diff --git a/components/script/dom/treewalker.rs b/components/script/dom/treewalker.rs
index c4097fc761a..7c749a5c502 100644
--- a/components/script/dom/treewalker.rs
+++ b/components/script/dom/treewalker.rs
@@ -9,7 +9,6 @@ use dom::bindings::codegen::Bindings::NodeFilterBinding::NodeFilterConstants;
 use dom::bindings::codegen::Bindings::TreeWalkerBinding;
 use dom::bindings::codegen::Bindings::TreeWalkerBinding::TreeWalkerMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutHeap};
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
@@ -46,7 +45,7 @@ impl TreeWalker {
                            what_to_show: u32,
                            filter: Filter) -> Root<TreeWalker> {
         reflect_dom_object(box TreeWalker::new_inherited(root_node, what_to_show, filter),
-                           GlobalRef::Window(document.window()),
+                           document.window(),
                            TreeWalkerBinding::Wrap)
     }
 
diff --git a/components/script/dom/uievent.rs b/components/script/dom/uievent.rs
index a0f35868662..99e25b80902 100644
--- a/components/script/dom/uievent.rs
+++ b/components/script/dom/uievent.rs
@@ -6,13 +6,13 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, RootedReference};
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use std::cell::Cell;
 use std::default::Default;
@@ -37,7 +37,7 @@ impl UIEvent {
 
     pub fn new_uninitialized(window: &Window) -> Root<UIEvent> {
         reflect_dom_object(box UIEvent::new_inherited(),
-                           GlobalRef::Window(window),
+                           window,
                            UIEventBinding::Wrap)
     }
 
@@ -52,12 +52,13 @@ impl UIEvent {
         ev
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &UIEventBinding::UIEventInit) -> Fallible<Root<UIEvent>> {
         let bubbles = EventBubbles::from(init.parent.bubbles);
         let cancelable = EventCancelable::from(init.parent.cancelable);
-        let event = UIEvent::new(global.as_window(), type_,
+        let event = UIEvent::new(global.as_window(),
+                                 type_,
                                  bubbles, cancelable,
                                  init.view.r(), init.detail);
         Ok(event)
diff --git a/components/script/dom/url.rs b/components/script/dom/url.rs
index bc686d23cc4..35dc4d896fa 100644
--- a/components/script/dom/url.rs
+++ b/components/script/dom/url.rs
@@ -6,11 +6,11 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
 use dom::bindings::codegen::Bindings::URLBinding::{self, URLMethods};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
 use dom::blob::Blob;
+use dom::globalscope::GlobalScope;
 use dom::urlhelper::UrlHelper;
 use dom::urlsearchparams::URLSearchParams;
 use ipc_channel::ipc;
@@ -44,7 +44,7 @@ impl URL {
         }
     }
 
-    pub fn new(global: GlobalRef, url: Url) -> Root<URL> {
+    pub fn new(global: &GlobalScope, url: Url) -> Root<URL> {
         reflect_dom_object(box URL::new_inherited(url),
                            global, URLBinding::Wrap)
     }
@@ -61,7 +61,7 @@ impl URL {
 
 impl URL {
     // https://url.spec.whatwg.org/#constructors
-    pub fn Constructor(global: GlobalRef, url: USVString,
+    pub fn Constructor(global: &GlobalScope, url: USVString,
                        base: Option<USVString>)
                        -> Fallible<Root<URL>> {
         let parsed_base = match base {
@@ -97,7 +97,7 @@ impl URL {
     }
 
     // https://url.spec.whatwg.org/#dom-url-domaintoasciidomain
-    pub fn DomainToASCII(_: GlobalRef, origin: USVString) -> USVString {
+    pub fn DomainToASCII(_: &GlobalScope, origin: USVString) -> USVString {
         // Step 1.
         let ascii_domain = Host::parse(&origin.0);
         if let Ok(Host::Domain(string)) = ascii_domain {
@@ -109,12 +109,12 @@ impl URL {
         }
     }
 
-    pub fn DomainToUnicode(_: GlobalRef, origin: USVString) -> USVString {
+    pub fn DomainToUnicode(_: &GlobalScope, origin: USVString) -> USVString {
         USVString(domain_to_unicode(&origin.0))
     }
 
     // https://w3c.github.io/FileAPI/#dfn-createObjectURL
-    pub fn CreateObjectURL(global: GlobalRef, blob: &Blob) -> DOMString {
+    pub fn CreateObjectURL(global: &GlobalScope, blob: &Blob) -> DOMString {
         /// XXX: Second field is an unicode-serialized Origin, it is a temporary workaround
         ///      and should not be trusted. See issue https://github.com/servo/servo/issues/11722
         let origin = get_blob_origin(&global.get_url());
@@ -131,7 +131,7 @@ impl URL {
     }
 
     // https://w3c.github.io/FileAPI/#dfn-revokeObjectURL
-    pub fn RevokeObjectURL(global: GlobalRef, url: DOMString) {
+    pub fn RevokeObjectURL(global: &GlobalScope, url: DOMString) {
         /*
             If the url refers to a Blob that has a readability state of CLOSED OR
             if the value provided for the url argument is not a Blob URL, OR
@@ -283,7 +283,9 @@ impl URLMethods for URL {
 
     // https://url.spec.whatwg.org/#dom-url-searchparams
     fn SearchParams(&self) -> Root<URLSearchParams> {
-        self.search_params.or_init(|| URLSearchParams::new(self.global().r(), Some(self)))
+        self.search_params.or_init(|| {
+            URLSearchParams::new(&self.global(), Some(self))
+        })
     }
 
     // https://url.spec.whatwg.org/#dom-url-href
diff --git a/components/script/dom/urlsearchparams.rs b/components/script/dom/urlsearchparams.rs
index 44eadea0932..2718f278dc3 100644
--- a/components/script/dom/urlsearchparams.rs
+++ b/components/script/dom/urlsearchparams.rs
@@ -7,11 +7,11 @@ use dom::bindings::codegen::Bindings::URLSearchParamsBinding;
 use dom::bindings::codegen::Bindings::URLSearchParamsBinding::URLSearchParamsMethods;
 use dom::bindings::codegen::UnionTypes::USVStringOrURLSearchParams;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
 use dom::bindings::weakref::MutableWeakRef;
+use dom::globalscope::GlobalScope;
 use dom::url::URL;
 use encoding::types::EncodingRef;
 use url::form_urlencoded;
@@ -35,13 +35,13 @@ impl URLSearchParams {
         }
     }
 
-    pub fn new(global: GlobalRef, url: Option<&URL>) -> Root<URLSearchParams> {
+    pub fn new(global: &GlobalScope, url: Option<&URL>) -> Root<URLSearchParams> {
         reflect_dom_object(box URLSearchParams::new_inherited(url), global,
                            URLSearchParamsBinding::Wrap)
     }
 
     // https://url.spec.whatwg.org/#dom-urlsearchparams-urlsearchparams
-    pub fn Constructor(global: GlobalRef, init: Option<USVStringOrURLSearchParams>) ->
+    pub fn Constructor(global: &GlobalScope, init: Option<USVStringOrURLSearchParams>) ->
                        Fallible<Root<URLSearchParams>> {
         // Step 1.
         let query = URLSearchParams::new(global, None);
diff --git a/components/script/dom/validitystate.rs b/components/script/dom/validitystate.rs
index 7595566f275..938320b7254 100644
--- a/components/script/dom/validitystate.rs
+++ b/components/script/dom/validitystate.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::ValidityStateBinding;
 use dom::bindings::codegen::Bindings::ValidityStateBinding::ValidityStateMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::element::Element;
@@ -47,7 +46,7 @@ impl ValidityState {
 
     pub fn new(window: &Window, element: &Element) -> Root<ValidityState> {
         reflect_dom_object(box ValidityState::new_inherited(element),
-                           GlobalRef::Window(window),
+                           window,
                            ValidityStateBinding::Wrap)
     }
 }
diff --git a/components/script/dom/webglactiveinfo.rs b/components/script/dom/webglactiveinfo.rs
index 00f70b682b7..ff82ce3b05f 100644
--- a/components/script/dom/webglactiveinfo.rs
+++ b/components/script/dom/webglactiveinfo.rs
@@ -5,10 +5,10 @@
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use dom::bindings::codegen::Bindings::WebGLActiveInfoBinding;
 use dom::bindings::codegen::Bindings::WebGLActiveInfoBinding::WebGLActiveInfoMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct WebGLActiveInfo {
@@ -29,7 +29,7 @@ impl WebGLActiveInfo {
         }
     }
 
-    pub fn new(global: GlobalRef, size: i32, ty: u32, name: DOMString) -> Root<WebGLActiveInfo> {
+    pub fn new(global: &GlobalScope, size: i32, ty: u32, name: DOMString) -> Root<WebGLActiveInfo> {
         reflect_dom_object(box WebGLActiveInfo::new_inherited(size, ty, name), global, WebGLActiveInfoBinding::Wrap)
     }
 }
diff --git a/components/script/dom/webglbuffer.rs b/components/script/dom/webglbuffer.rs
index 3899d417b38..af8f83d256d 100644
--- a/components/script/dom/webglbuffer.rs
+++ b/components/script/dom/webglbuffer.rs
@@ -5,9 +5,9 @@
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use canvas_traits::CanvasMsg;
 use dom::bindings::codegen::Bindings::WebGLBufferBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
+use dom::globalscope::GlobalScope;
 use dom::webglobject::WebGLObject;
 use ipc_channel::ipc::{self, IpcSender};
 use std::cell::Cell;
@@ -39,7 +39,7 @@ impl WebGLBuffer {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(global: &GlobalScope, renderer: IpcSender<CanvasMsg>)
                      -> Option<Root<WebGLBuffer>> {
         let (sender, receiver) = ipc::channel().unwrap();
         renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateBuffer(sender))).unwrap();
@@ -48,7 +48,7 @@ impl WebGLBuffer {
         result.map(|buffer_id| WebGLBuffer::new(global, renderer, buffer_id))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLBufferId)
               -> Root<WebGLBuffer> {
diff --git a/components/script/dom/webglcontextevent.rs b/components/script/dom/webglcontextevent.rs
index 9c73a9f6b65..079218ab3ae 100644
--- a/components/script/dom/webglcontextevent.rs
+++ b/components/script/dom/webglcontextevent.rs
@@ -7,12 +7,12 @@ use dom::bindings::codegen::Bindings::WebGLContextEventBinding;
 use dom::bindings::codegen::Bindings::WebGLContextEventBinding::WebGLContextEventInit;
 use dom::bindings::codegen::Bindings::WebGLContextEventBinding::WebGLContextEventMethods;
 use dom::bindings::error::Fallible;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use string_cache::Atom;
 
 #[dom_struct]
@@ -41,7 +41,7 @@ impl WebGLContextEvent {
         }
     }
 
-    pub fn new_uninitialized(global_ref: GlobalRef) -> Root<WebGLContextEvent> {
+    pub fn new_uninitialized(global_ref: &GlobalScope) -> Root<WebGLContextEvent> {
         // according to https://www.khronos.org/registry/webgl/specs/1.0/#5.15 this is
         // additional information or the empty string if no additional information is
         // available.
@@ -52,7 +52,7 @@ impl WebGLContextEvent {
                         WebGLContextEventBinding::Wrap)
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                type_: Atom,
                bubbles: EventBubbles,
                cancelable: EventCancelable,
@@ -70,7 +70,7 @@ impl WebGLContextEvent {
         event
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        type_: DOMString,
                        init: &WebGLContextEventInit) -> Fallible<Root<WebGLContextEvent>> {
         let status_message = match init.statusMessage.as_ref() {
@@ -82,7 +82,8 @@ impl WebGLContextEvent {
 
         let cancelable = EventCancelable::from(init.parent.cancelable);
 
-        Ok(WebGLContextEvent::new(global, Atom::from(type_),
+        Ok(WebGLContextEvent::new(global,
+                                  Atom::from(type_),
                                   bubbles,
                                   cancelable,
                                   status_message))
diff --git a/components/script/dom/webglframebuffer.rs b/components/script/dom/webglframebuffer.rs
index cd212d644bf..22749832389 100644
--- a/components/script/dom/webglframebuffer.rs
+++ b/components/script/dom/webglframebuffer.rs
@@ -6,9 +6,9 @@
 use canvas_traits::CanvasMsg;
 use dom::bindings::codegen::Bindings::WebGLFramebufferBinding;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
+use dom::globalscope::GlobalScope;
 use dom::webglobject::WebGLObject;
 use ipc_channel::ipc::{self, IpcSender};
 use std::cell::Cell;
@@ -38,7 +38,7 @@ impl WebGLFramebuffer {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(global: &GlobalScope, renderer: IpcSender<CanvasMsg>)
                      -> Option<Root<WebGLFramebuffer>> {
         let (sender, receiver) = ipc::channel().unwrap();
         renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateFramebuffer(sender))).unwrap();
@@ -47,7 +47,7 @@ impl WebGLFramebuffer {
         result.map(|fb_id| WebGLFramebuffer::new(global, renderer, fb_id))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLFramebufferId)
                -> Root<WebGLFramebuffer> {
diff --git a/components/script/dom/webglobject.rs b/components/script/dom/webglobject.rs
index c6bc733de62..0964fc5d0cf 100644
--- a/components/script/dom/webglobject.rs
+++ b/components/script/dom/webglobject.rs
@@ -4,9 +4,9 @@
 
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use dom::bindings::codegen::Bindings::WebGLObjectBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct WebGLObject {
@@ -20,7 +20,7 @@ impl WebGLObject {
         }
     }
 
-    pub fn new(global: GlobalRef) -> Root<WebGLObject> {
+    pub fn new(global: &GlobalScope) -> Root<WebGLObject> {
         reflect_dom_object(box WebGLObject::new_inherited(), global, WebGLObjectBinding::Wrap)
     }
 }
diff --git a/components/script/dom/webglprogram.rs b/components/script/dom/webglprogram.rs
index 6382897efb3..98139081c3b 100644
--- a/components/script/dom/webglprogram.rs
+++ b/components/script/dom/webglprogram.rs
@@ -6,10 +6,10 @@
 use canvas_traits::CanvasMsg;
 use dom::bindings::codegen::Bindings::WebGLProgramBinding;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use dom::webglactiveinfo::WebGLActiveInfo;
 use dom::webglobject::WebGLObject;
 use dom::webglrenderingcontext::MAX_UNIFORM_AND_ATTRIBUTE_LEN;
@@ -48,7 +48,7 @@ impl WebGLProgram {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(global: &GlobalScope, renderer: IpcSender<CanvasMsg>)
                      -> Option<Root<WebGLProgram>> {
         let (sender, receiver) = ipc::channel().unwrap();
         renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateProgram(sender))).unwrap();
@@ -57,7 +57,7 @@ impl WebGLProgram {
         result.map(|program_id| WebGLProgram::new(global, renderer, program_id))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLProgramId)
                -> Root<WebGLProgram> {
@@ -230,7 +230,7 @@ impl WebGLProgram {
             .unwrap();
 
         receiver.recv().unwrap().map(|(size, ty, name)|
-            WebGLActiveInfo::new(self.global().r(), size, ty, DOMString::from(name)))
+            WebGLActiveInfo::new(&self.global(), size, ty, DOMString::from(name)))
     }
 
     /// glGetActiveAttrib
@@ -244,7 +244,7 @@ impl WebGLProgram {
             .unwrap();
 
         receiver.recv().unwrap().map(|(size, ty, name)|
-            WebGLActiveInfo::new(self.global().r(), size, ty, DOMString::from(name)))
+            WebGLActiveInfo::new(&self.global(), size, ty, DOMString::from(name)))
     }
 
     /// glGetAttribLocation
diff --git a/components/script/dom/webglrenderbuffer.rs b/components/script/dom/webglrenderbuffer.rs
index b7e89f2eb22..de4eaa2d2c8 100644
--- a/components/script/dom/webglrenderbuffer.rs
+++ b/components/script/dom/webglrenderbuffer.rs
@@ -5,9 +5,9 @@
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use canvas_traits::CanvasMsg;
 use dom::bindings::codegen::Bindings::WebGLRenderbufferBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
+use dom::globalscope::GlobalScope;
 use dom::webglobject::WebGLObject;
 use ipc_channel::ipc::{self, IpcSender};
 use std::cell::Cell;
@@ -36,7 +36,7 @@ impl WebGLRenderbuffer {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(global: &GlobalScope, renderer: IpcSender<CanvasMsg>)
                      -> Option<Root<WebGLRenderbuffer>> {
         let (sender, receiver) = ipc::channel().unwrap();
         renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateRenderbuffer(sender))).unwrap();
@@ -45,7 +45,7 @@ impl WebGLRenderbuffer {
         result.map(|renderbuffer_id| WebGLRenderbuffer::new(global, renderer, renderbuffer_id))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLRenderbufferId)
                -> Root<WebGLRenderbuffer> {
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index b69f11146fd..312357fd3d2 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -10,12 +10,12 @@ use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderi
 use dom::bindings::codegen::UnionTypes::ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement;
 use dom::bindings::conversions::{ToJSValConvertible, array_buffer_view_data, array_buffer_view_data_checked};
 use dom::bindings::conversions::{array_buffer_view_to_vec, array_buffer_view_to_vec_checked};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap, Root};
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::htmlcanvaselement::HTMLCanvasElement;
 use dom::htmlcanvaselement::utils as canvas_utils;
 use dom::node::{Node, NodeDamage, window_from_node};
@@ -127,7 +127,7 @@ pub struct WebGLRenderingContext {
 }
 
 impl WebGLRenderingContext {
-    fn new_inherited(global: GlobalRef,
+    fn new_inherited(global: &GlobalScope,
                      canvas: &HTMLCanvasElement,
                      size: Size2D<i32>,
                      attrs: GLContextAttributes)
@@ -159,11 +159,10 @@ impl WebGLRenderingContext {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(global: GlobalRef, canvas: &HTMLCanvasElement, size: Size2D<i32>, attrs: GLContextAttributes)
+    pub fn new(global: &GlobalScope, canvas: &HTMLCanvasElement, size: Size2D<i32>, attrs: GLContextAttributes)
                -> Option<Root<WebGLRenderingContext>> {
         match WebGLRenderingContext::new_inherited(global, canvas, size, attrs) {
-            Ok(ctx) => Some(reflect_dom_object(box ctx, global,
-                                               WebGLRenderingContextBinding::Wrap)),
+            Ok(ctx) => Some(reflect_dom_object(box ctx, global, WebGLRenderingContextBinding::Wrap)),
             Err(msg) => {
                 error!("Couldn't create WebGLRenderingContext: {}", msg);
                 let event = WebGLContextEvent::new(global,
@@ -1154,27 +1153,27 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // generated objects, either here or in the webgl thread
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
     fn CreateBuffer(&self) -> Option<Root<WebGLBuffer>> {
-        WebGLBuffer::maybe_new(self.global().r(), self.ipc_renderer.clone())
+        WebGLBuffer::maybe_new(&self.global(), self.ipc_renderer.clone())
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.6
     fn CreateFramebuffer(&self) -> Option<Root<WebGLFramebuffer>> {
-        WebGLFramebuffer::maybe_new(self.global().r(), self.ipc_renderer.clone())
+        WebGLFramebuffer::maybe_new(&self.global(), self.ipc_renderer.clone())
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
     fn CreateRenderbuffer(&self) -> Option<Root<WebGLRenderbuffer>> {
-        WebGLRenderbuffer::maybe_new(self.global().r(), self.ipc_renderer.clone())
+        WebGLRenderbuffer::maybe_new(&self.global(), self.ipc_renderer.clone())
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.8
     fn CreateTexture(&self) -> Option<Root<WebGLTexture>> {
-        WebGLTexture::maybe_new(self.global().r(), self.ipc_renderer.clone())
+        WebGLTexture::maybe_new(&self.global(), self.ipc_renderer.clone())
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
     fn CreateProgram(&self) -> Option<Root<WebGLProgram>> {
-        WebGLProgram::maybe_new(self.global().r(), self.ipc_renderer.clone())
+        WebGLProgram::maybe_new(&self.global(), self.ipc_renderer.clone())
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
@@ -1186,7 +1185,7 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
                 return None;
             }
         }
-        WebGLShader::maybe_new(self.global().r(), self.ipc_renderer.clone(), shader_type)
+        WebGLShader::maybe_new(&self.global(), self.ipc_renderer.clone(), shader_type)
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
@@ -1480,7 +1479,7 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
                           name: DOMString) -> Option<Root<WebGLUniformLocation>> {
         program.and_then(|p| {
             handle_potential_webgl_error!(self, p.get_uniform_location(name), None)
-                .map(|location| WebGLUniformLocation::new(self.global().r(), location, p.id()))
+                .map(|location| WebGLUniformLocation::new(&self.global(), location, p.id()))
         })
     }
 
diff --git a/components/script/dom/webglshader.rs b/components/script/dom/webglshader.rs
index ca2555faa8e..82d1b88a7da 100644
--- a/components/script/dom/webglshader.rs
+++ b/components/script/dom/webglshader.rs
@@ -7,10 +7,10 @@ use angle::hl::{BuiltInResources, Output, ShaderValidator};
 use canvas_traits::CanvasMsg;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::WebGLShaderBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use dom::webglobject::WebGLObject;
 use ipc_channel::ipc::{self, IpcSender};
 use std::cell::Cell;
@@ -65,7 +65,7 @@ impl WebGLShader {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef,
+    pub fn maybe_new(global: &GlobalScope,
                      renderer: IpcSender<CanvasMsg>,
                      shader_type: u32) -> Option<Root<WebGLShader>> {
         let (sender, receiver) = ipc::channel().unwrap();
@@ -75,7 +75,7 @@ impl WebGLShader {
         result.map(|shader_id| WebGLShader::new(global, renderer, shader_id, shader_type))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLShaderId,
                shader_type: u32)
diff --git a/components/script/dom/webglshaderprecisionformat.rs b/components/script/dom/webglshaderprecisionformat.rs
index 6cd78b8d51a..18ba8c189a5 100644
--- a/components/script/dom/webglshaderprecisionformat.rs
+++ b/components/script/dom/webglshaderprecisionformat.rs
@@ -5,9 +5,9 @@
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use dom::bindings::codegen::Bindings::WebGLShaderPrecisionFormatBinding;
 use dom::bindings::codegen::Bindings::WebGLShaderPrecisionFormatBinding::WebGLShaderPrecisionFormatMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 
 #[dom_struct]
 pub struct WebGLShaderPrecisionFormat {
@@ -27,7 +27,7 @@ impl WebGLShaderPrecisionFormat {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                range_min: i32,
                range_max: i32,
                precision: i32) -> Root<WebGLShaderPrecisionFormat> {
diff --git a/components/script/dom/webgltexture.rs b/components/script/dom/webgltexture.rs
index e189835ee9d..31fdaafcffd 100644
--- a/components/script/dom/webgltexture.rs
+++ b/components/script/dom/webgltexture.rs
@@ -7,9 +7,9 @@ use canvas_traits::CanvasMsg;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
 use dom::bindings::codegen::Bindings::WebGLTextureBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
+use dom::globalscope::GlobalScope;
 use dom::webgl_validations::types::{TexImageTarget, TexFormat, TexDataType};
 use dom::webglobject::WebGLObject;
 use ipc_channel::ipc::{self, IpcSender};
@@ -60,7 +60,7 @@ impl WebGLTexture {
         }
     }
 
-    pub fn maybe_new(global: GlobalRef, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(global: &GlobalScope, renderer: IpcSender<CanvasMsg>)
                      -> Option<Root<WebGLTexture>> {
         let (sender, receiver) = ipc::channel().unwrap();
         renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateTexture(sender))).unwrap();
@@ -69,7 +69,7 @@ impl WebGLTexture {
         result.map(|texture_id| WebGLTexture::new(global, renderer, texture_id))
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                renderer: IpcSender<CanvasMsg>,
                id: WebGLTextureId)
                -> Root<WebGLTexture> {
diff --git a/components/script/dom/webgluniformlocation.rs b/components/script/dom/webgluniformlocation.rs
index f52cb899eb8..6e0683ec833 100644
--- a/components/script/dom/webgluniformlocation.rs
+++ b/components/script/dom/webgluniformlocation.rs
@@ -4,9 +4,9 @@
 
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
 use dom::bindings::codegen::Bindings::WebGLUniformLocationBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::globalscope::GlobalScope;
 use webrender_traits::WebGLProgramId;
 
 #[dom_struct]
@@ -27,7 +27,7 @@ impl WebGLUniformLocation {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                id: i32,
                program_id: WebGLProgramId)
                -> Root<WebGLUniformLocation> {
diff --git a/components/script/dom/webidls/GlobalScope.webidl b/components/script/dom/webidls/GlobalScope.webidl
new file mode 100644
index 00000000000..7dab4f3afa7
--- /dev/null
+++ b/components/script/dom/webidls/GlobalScope.webidl
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This interface is entirely internal to Servo, and should not be accessible to
+// web pages.
+
+[Exposed=(Window,Worker),
+ Inline]
+interface GlobalScope : EventTarget {};
diff --git a/components/script/dom/webidls/Window.webidl b/components/script/dom/webidls/Window.webidl
index 84fb4d754de..8fdc636a732 100644
--- a/components/script/dom/webidls/Window.webidl
+++ b/components/script/dom/webidls/Window.webidl
@@ -4,7 +4,7 @@
 
 // https://html.spec.whatwg.org/multipage/#window
 [PrimaryGlobal, Exposed=(Window,Worker)]
-/*sealed*/ interface Window : EventTarget {
+/*sealed*/ interface Window : GlobalScope {
   // the current browsing context
   [Unforgeable] readonly attribute WindowProxy window;
   [BinaryName="Self_", Replaceable] readonly attribute WindowProxy self;
diff --git a/components/script/dom/webidls/WorkerGlobalScope.webidl b/components/script/dom/webidls/WorkerGlobalScope.webidl
index 186e5cd7fee..dcdd2957d43 100644
--- a/components/script/dom/webidls/WorkerGlobalScope.webidl
+++ b/components/script/dom/webidls/WorkerGlobalScope.webidl
@@ -4,7 +4,7 @@
 
 // https://html.spec.whatwg.org/multipage/#workerglobalscope
 [Abstract, Exposed=Worker]
-interface WorkerGlobalScope : EventTarget {
+interface WorkerGlobalScope : GlobalScope {
   [BinaryName="Self_"] readonly attribute WorkerGlobalScope self;
   readonly attribute WorkerLocation location;
 
diff --git a/components/script/dom/websocket.rs b/components/script/dom/websocket.rs
index df9c2e5ed34..2582367ec08 100644
--- a/components/script/dom/websocket.rs
+++ b/components/script/dom/websocket.rs
@@ -10,7 +10,6 @@ use dom::bindings::codegen::Bindings::WebSocketBinding::{BinaryType, WebSocketMe
 use dom::bindings::codegen::UnionTypes::StringOrStringSequence;
 use dom::bindings::conversions::ToJSValConvertible;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
@@ -20,6 +19,7 @@ use dom::blob::{Blob, BlobImpl};
 use dom::closeevent::CloseEvent;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::messageevent::MessageEvent;
 use dom::urlhelper::UrlHelper;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
@@ -190,12 +190,12 @@ impl WebSocket {
         }
     }
 
-    fn new(global: GlobalRef, url: Url) -> Root<WebSocket> {
+    fn new(global: &GlobalScope, url: Url) -> Root<WebSocket> {
         reflect_dom_object(box WebSocket::new_inherited(url),
                            global, WebSocketBinding::Wrap)
     }
 
-    pub fn Constructor(global: GlobalRef,
+    pub fn Constructor(global: &GlobalScope,
                        url: DOMString,
                        protocols: Option<StringOrStringSequence>)
                        -> Fallible<Root<WebSocket>> {
@@ -328,8 +328,10 @@ impl WebSocket {
                 address: address,
             };
 
-            let global = self.global();
-            global.r().script_chan().send(CommonScriptMsg::RunnableMsg(WebSocketEvent, task)).unwrap();
+            self.global()
+                .script_chan()
+                .send(CommonScriptMsg::RunnableMsg(WebSocketEvent, task))
+                .unwrap();
         }
 
         Ok(true)
@@ -434,7 +436,7 @@ impl WebSocketMethods for WebSocket {
                 self.ready_state.set(WebSocketRequestState::Closing);
 
                 let address = Trusted::new(self);
-                let sender = self.global().r().networking_task_source();
+                let sender = self.global().networking_task_source();
                 fail_the_websocket_connection(address, sender);
             }
             WebSocketRequestState::Open => {
@@ -465,11 +467,10 @@ impl Runnable for ConnectionEstablishedTask {
 
     fn handler(self: Box<Self>) {
         let ws = self.address.root();
-        let global = ws.r().global();
 
         // Step 1: Protocols.
         if !self.protocols.is_empty() && self.headers.get::<WebSocketProtocol>().is_none() {
-            let sender = global.r().networking_task_source();
+            let sender = ws.global().networking_task_source();
             fail_the_websocket_connection(self.address, sender);
             return;
         }
@@ -490,9 +491,8 @@ impl Runnable for ConnectionEstablishedTask {
         if let Some(cookies) = self.headers.get_raw("set-cookie") {
             for cookie in cookies.iter() {
                 if let Ok(cookie_value) = String::from_utf8(cookie.clone()) {
-                    let _ = ws.global().r().core_resource_thread().send(SetCookiesForUrl(ws.url.clone(),
-                                                                                         cookie_value,
-                                                                                         HTTP));
+                    let _ = ws.global().core_resource_thread().send(
+                        SetCookiesForUrl(ws.url.clone(), cookie_value, HTTP));
                 }
             }
         }
@@ -534,8 +534,6 @@ impl Runnable for CloseTask {
 
     fn handler(self: Box<Self>) {
         let ws = self.address.root();
-        let ws = ws.r();
-        let global = ws.global();
 
         if ws.ready_state.get() == WebSocketRequestState::Closed {
             // Do nothing if already closed.
@@ -557,7 +555,7 @@ impl Runnable for CloseTask {
         let clean_close = !self.failed;
         let code = self.code.unwrap_or(close_code::NO_STATUS);
         let reason = DOMString::from(self.reason.unwrap_or("".to_owned()));
-        let close_event = CloseEvent::new(global.r(),
+        let close_event = CloseEvent::new(&ws.global(),
                                           atom!("close"),
                                           EventBubbles::DoesNotBubble,
                                           EventCancelable::NotCancelable,
@@ -588,10 +586,10 @@ impl Runnable for MessageReceivedTask {
         }
 
         // Step 2-5.
-        let global = ws.r().global();
+        let global = ws.global();
         // global.get_cx() returns a valid `JSContext` pointer, so this is safe.
         unsafe {
-            let cx = global.r().get_cx();
+            let cx = global.get_cx();
             let _ac = JSAutoCompartment::new(cx, ws.reflector().get_jsobject().get());
             rooted!(in(cx) let mut message = UndefinedValue());
             match self.message {
@@ -599,7 +597,7 @@ impl Runnable for MessageReceivedTask {
                 MessageData::Binary(data) => {
                     match ws.binary_type.get() {
                         BinaryType::Blob => {
-                            let blob = Blob::new(global.r(), BlobImpl::new_from_bytes(data), "".to_owned());
+                            let blob = Blob::new(&global, BlobImpl::new_from_bytes(data), "".to_owned());
                             blob.to_jsval(cx, message.handle_mut());
                         }
                         BinaryType::Arraybuffer => {
@@ -615,7 +613,7 @@ impl Runnable for MessageReceivedTask {
                     }
                 },
             }
-            MessageEvent::dispatch_jsval(ws.upcast(), global.r(), message.handle());
+            MessageEvent::dispatch_jsval(ws.upcast(), &global, message.handle());
         }
     }
 }
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 3ac5c4e37f9..9bb813a2946 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
-use devtools_traits::{ScriptToDevtoolsControlMsg, TimelineMarker, TimelineMarkerType, WorkerId};
+use devtools_traits::{ScriptToDevtoolsControlMsg, TimelineMarker, TimelineMarkerType};
 use dom::bindings::callback::ExceptionHandling;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::DocumentBinding::{DocumentMethods, DocumentReadyState};
@@ -16,8 +16,7 @@ use dom::bindings::codegen::Bindings::RequestBinding::RequestInit;
 use dom::bindings::codegen::Bindings::WindowBinding::{self, FrameRequestCallback, WindowMethods};
 use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, ScrollToOptions};
 use dom::bindings::codegen::UnionTypes::RequestOrUSVString;
-use dom::bindings::error::{Error, ErrorInfo, ErrorResult, Fallible};
-use dom::bindings::global::{GlobalRef, global_root_from_object};
+use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::num::Finite;
@@ -27,14 +26,12 @@ use dom::bindings::str::DOMString;
 use dom::bindings::structuredclone::StructuredCloneData;
 use dom::bindings::utils::{GlobalStaticData, WindowProxyHandler};
 use dom::browsingcontext::BrowsingContext;
-use dom::console::TimerSet;
 use dom::crypto::Crypto;
 use dom::cssstyledeclaration::{CSSModificationAccess, CSSStyleDeclaration};
 use dom::document::Document;
 use dom::element::Element;
-use dom::errorevent::ErrorEvent;
-use dom::event::{Event, EventBubbles, EventCancelable};
-use dom::eventtarget::EventTarget;
+use dom::event::Event;
+use dom::globalscope::GlobalScope;
 use dom::history::History;
 use dom::htmliframeelement::build_mozbrowser_custom_event;
 use dom::location::Location;
@@ -73,8 +70,8 @@ use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptThreadEventC
 use script_thread::{MainThreadScriptChan, MainThreadScriptMsg, Runnable, RunnableWrapper};
 use script_thread::SendableMainThreadScriptChan;
 use script_traits::{ConstellationControlMsg, MozBrowserEvent, UntrustedNodeAddress};
-use script_traits::{DocumentState, MsDuration, TimerEvent, TimerEventId};
-use script_traits::{ScriptMsg as ConstellationMsg, TimerEventRequest, TimerSource, WindowSizeData};
+use script_traits::{DocumentState, TimerEvent, TimerEventId};
+use script_traits::{ScriptMsg as ConstellationMsg, TimerEventRequest, WindowSizeData};
 use script_traits::webdriver_msg::{WebDriverJSError, WebDriverJSResult};
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
@@ -99,7 +96,7 @@ use task_source::history_traversal::HistoryTraversalTaskSource;
 use task_source::networking::NetworkingTaskSource;
 use task_source::user_interaction::UserInteractionTaskSource;
 use time;
-use timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle, OneshotTimers, TimerCallback};
+use timers::{IsInterval, TimerCallback};
 #[cfg(any(target_os = "macos", target_os = "linux", target_os = "windows"))]
 use tinyfiledialogs::{self, MessageBoxIcon};
 use url::Url;
@@ -143,7 +140,7 @@ pub type ScrollPoint = Point2D<Au>;
 
 #[dom_struct]
 pub struct Window {
-    eventtarget: EventTarget,
+    globalscope: GlobalScope,
     #[ignore_heap_size_of = "trait objects are hard"]
     script_chan: MainThreadScriptChan,
     #[ignore_heap_size_of = "task sources are hard"]
@@ -156,7 +153,6 @@ pub struct Window {
     history_traversal_task_source: HistoryTraversalTaskSource,
     #[ignore_heap_size_of = "task sources are hard"]
     file_reading_task_source: FileReadingTaskSource,
-    crypto: MutNullableHeap<JS<Crypto>>,
     navigator: MutNullableHeap<JS<Navigator>>,
     #[ignore_heap_size_of = "channels are hard"]
     image_cache_thread: ImageCacheThread,
@@ -171,39 +167,16 @@ pub struct Window {
     session_storage: MutNullableHeap<JS<Storage>>,
     local_storage: MutNullableHeap<JS<Storage>>,
     status: DOMRefCell<DOMString>,
-    #[ignore_heap_size_of = "channels are hard"]
-    scheduler_chan: IpcSender<TimerEventRequest>,
-    timers: OneshotTimers,
-
-    next_worker_id: Cell<WorkerId>,
-
-    /// For sending messages to the memory profiler.
-    #[ignore_heap_size_of = "channels are hard"]
-    mem_profiler_chan: mem::ProfilerChan,
 
-    /// For sending messages to the memory profiler.
-    #[ignore_heap_size_of = "channels are hard"]
-    time_profiler_chan: ProfilerChan,
-
-    /// For providing instructions to an optional devtools server.
-    #[ignore_heap_size_of = "channels are hard"]
-    devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     /// For sending timeline markers. Will be ignored if
     /// no devtools server
     devtools_markers: DOMRefCell<HashSet<TimelineMarkerType>>,
     #[ignore_heap_size_of = "channels are hard"]
     devtools_marker_sender: DOMRefCell<Option<IpcSender<TimelineMarker>>>,
 
-    /// A flag to indicate whether the developer tools have requested live updates of
-    /// page changes.
-    devtools_wants_updates: Cell<bool>,
-
     /// Pending resize event, if any.
     resize_event: Cell<Option<(WindowSizeData, WindowSizeType)>>,
 
-    /// Pipeline id associated with this page.
-    id: PipelineId,
-
     /// Parent id associated with this page, if any.
     parent_info: Option<(PipelineId, FrameType)>,
 
@@ -225,18 +198,10 @@ pub struct Window {
     /// The current size of the window, in pixels.
     window_size: Cell<Option<WindowSizeData>>,
 
-    /// Associated resource threads for use by DOM objects like XMLHttpRequest,
-    /// including resource_thread, filemanager_thread and storage_thread
-    resource_threads: ResourceThreads,
-
     /// A handle for communicating messages to the bluetooth thread.
     #[ignore_heap_size_of = "channels are hard"]
     bluetooth_thread: IpcSender<BluetoothMethodMsg>,
 
-    /// A handle for communicating messages to the constellation thread.
-    #[ignore_heap_size_of = "channels are hard"]
-    constellation_chan: IpcSender<ConstellationMsg>,
-
     /// Pending scroll to fragment event, if any
     fragment_name: DOMRefCell<Option<String>>,
 
@@ -269,12 +234,6 @@ pub struct Window {
 
     /// A list of scroll offsets for each scrollable element.
     scroll_offsets: DOMRefCell<HashMap<UntrustedNodeAddress, Point2D<f32>>>,
-
-    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
-    in_error_reporting_mode: Cell<bool>,
-
-    /// Timers used by the Console API.
-    console_timers: TimerSet,
 }
 
 impl Window {
@@ -320,17 +279,6 @@ impl Window {
         self.image_cache_chan.clone()
     }
 
-    pub fn get_next_worker_id(&self) -> WorkerId {
-        let worker_id = self.next_worker_id.get();
-        let WorkerId(id_num) = worker_id;
-        self.next_worker_id.set(WorkerId(id_num + 1));
-        worker_id
-    }
-
-    pub fn pipeline_id(&self) -> PipelineId {
-        self.id
-    }
-
     pub fn parent_info(&self) -> Option<(PipelineId, FrameType)> {
         self.parent_info
     }
@@ -464,7 +412,11 @@ impl WindowMethods for Window {
         }
 
         let (sender, receiver) = ipc::channel().unwrap();
-        self.constellation_chan().send(ConstellationMsg::Alert(self.pipeline_id(), s.to_string(), sender)).unwrap();
+        let global_scope = self.upcast::<GlobalScope>();
+        global_scope
+            .constellation_chan()
+            .send(ConstellationMsg::Alert(global_scope.pipeline_id(), s.to_string(), sender))
+            .unwrap();
 
         let should_display_alert_dialog = receiver.recv().unwrap();
         if should_display_alert_dialog {
@@ -474,7 +426,9 @@ impl WindowMethods for Window {
 
     // https://html.spec.whatwg.org/multipage/#dom-window-close
     fn Close(&self) {
-        self.main_thread_script_chan().send(MainThreadScriptMsg::ExitWindow(self.id.clone())).unwrap();
+        self.main_thread_script_chan()
+            .send(MainThreadScriptMsg::ExitWindow(self.upcast::<GlobalScope>().pipeline_id()))
+            .unwrap();
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-document-2
@@ -494,17 +448,17 @@ impl WindowMethods for Window {
 
     // https://html.spec.whatwg.org/multipage/#dom-sessionstorage
     fn SessionStorage(&self) -> Root<Storage> {
-        self.session_storage.or_init(|| Storage::new(&GlobalRef::Window(self), StorageType::Session))
+        self.session_storage.or_init(|| Storage::new(self.upcast(), StorageType::Session))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-localstorage
     fn LocalStorage(&self) -> Root<Storage> {
-        self.local_storage.or_init(|| Storage::new(&GlobalRef::Window(self), StorageType::Local))
+        self.local_storage.or_init(|| Storage::new(self.upcast(), StorageType::Local))
     }
 
     // https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#dfn-GlobalCrypto
     fn Crypto(&self) -> Root<Crypto> {
-        self.crypto.or_init(|| Crypto::new(GlobalRef::Window(self)))
+        self.upcast::<GlobalScope>().crypto()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-frameelement
@@ -519,47 +473,43 @@ impl WindowMethods for Window {
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout
     fn SetTimeout(&self, _cx: *mut JSContext, callback: Rc<Function>, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Window(self),
-                                            TimerCallback::FunctionTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::NonInterval,
-                                            TimerSource::FromWindow(self.id.clone()))
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::FunctionTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::NonInterval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout
     fn SetTimeout_(&self, _cx: *mut JSContext, callback: DOMString, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Window(self),
-                                            TimerCallback::StringTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::NonInterval,
-                                            TimerSource::FromWindow(self.id.clone()))
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::StringTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::NonInterval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-cleartimeout
     fn ClearTimeout(&self, handle: i32) {
-        self.timers.clear_timeout_or_interval(GlobalRef::Window(self), handle);
+        self.upcast::<GlobalScope>().clear_timeout_or_interval(handle);
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
     fn SetInterval(&self, _cx: *mut JSContext, callback: Rc<Function>, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Window(self),
-                                            TimerCallback::FunctionTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::Interval,
-                                            TimerSource::FromWindow(self.id.clone()))
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::FunctionTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::Interval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
     fn SetInterval_(&self, _cx: *mut JSContext, callback: DOMString, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Window(self),
-                                            TimerCallback::StringTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::Interval,
-                                            TimerSource::FromWindow(self.id.clone()))
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::StringTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::Interval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
@@ -825,7 +775,10 @@ impl WindowMethods for Window {
         // Step 1
         //TODO determine if this operation is allowed
         let size = Size2D::new(x.to_u32().unwrap_or(1), y.to_u32().unwrap_or(1));
-        self.constellation_chan.send(ConstellationMsg::ResizeTo(size)).unwrap()
+        self.upcast::<GlobalScope>()
+            .constellation_chan()
+            .send(ConstellationMsg::ResizeTo(size))
+            .unwrap()
     }
 
     // https://drafts.csswg.org/cssom-view/#dom-window-resizeby
@@ -840,7 +793,10 @@ impl WindowMethods for Window {
         // Step 1
         //TODO determine if this operation is allowed
         let point = Point2D::new(x, y);
-        self.constellation_chan.send(ConstellationMsg::MoveTo(point)).unwrap()
+        self.upcast::<GlobalScope>()
+            .constellation_chan()
+            .send(ConstellationMsg::MoveTo(point))
+            .unwrap()
     }
 
     // https://drafts.csswg.org/cssom-view/#dom-window-moveby
@@ -904,14 +860,14 @@ impl WindowMethods for Window {
     #[allow(unrooted_must_root)]
     // https://fetch.spec.whatwg.org/#fetch-method
     fn Fetch(&self, input: RequestOrUSVString, init: &RequestInit) -> Rc<Promise> {
-        fetch::Fetch(self.global().r(), input, init)
+        fetch::Fetch(&self.upcast(), input, init)
     }
 }
 
 impl Window {
     pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
         RunnableWrapper {
-            cancelled: self.ignore_further_async_events.clone()
+            cancelled: Some(self.ignore_further_async_events.clone()),
         }
     }
 
@@ -1001,8 +957,10 @@ impl Window {
         // TODO (farodin91): Raise an event to stop the current_viewport
         self.update_viewport_for_scroll(x, y);
 
-        let message = ConstellationMsg::ScrollFragmentPoint(self.pipeline_id(), layer_id, point, smooth);
-        self.constellation_chan.send(message).unwrap();
+        let global_scope = self.upcast::<GlobalScope>();
+        let message = ConstellationMsg::ScrollFragmentPoint(
+            global_scope.pipeline_id(), layer_id, point, smooth);
+        global_scope.constellation_chan().send(message).unwrap();
     }
 
     pub fn update_viewport_for_scroll(&self, x: f32, y: f32) {
@@ -1013,7 +971,10 @@ impl Window {
 
     pub fn client_window(&self) -> (Size2D<u32>, Point2D<i32>) {
         let (send, recv) = ipc::channel::<(Size2D<u32>, Point2D<i32>)>().unwrap();
-        self.constellation_chan.send(ConstellationMsg::GetClientWindow(send)).unwrap();
+        self.upcast::<GlobalScope>()
+            .constellation_chan()
+            .send(ConstellationMsg::GetClientWindow(send))
+            .unwrap();
         recv.recv().unwrap_or((Size2D::zero(), Point2D::zero()))
     }
 
@@ -1054,7 +1015,7 @@ impl Window {
         let for_display = query_type == ReflowQueryType::NoQuery;
         if for_display && self.suppress_reflow.get() {
             debug!("Suppressing reflow pipeline {} for goal {:?} reason {:?} before FirstLoad or RefreshTick",
-                   self.id, goal, reason);
+                   self.upcast::<GlobalScope>().pipeline_id(), goal, reason);
             return false;
         }
 
@@ -1071,7 +1032,7 @@ impl Window {
 
         // On debug mode, print the reflow event information.
         if opts::get().relayout_event {
-            debug_reflow_events(self.id, &goal, &query_type, &reason);
+            debug_reflow_events(self.upcast::<GlobalScope>().pipeline_id(), &goal, &query_type, &reason);
         }
 
         let document = self.Document();
@@ -1176,8 +1137,9 @@ impl Window {
             let ready_state = document.ReadyState();
 
             if ready_state == DocumentReadyState::Complete && !reftest_wait {
-                let event = ConstellationMsg::SetDocumentState(self.id, DocumentState::Idle);
-                self.constellation_chan().send(event).unwrap();
+                let global_scope = self.upcast::<GlobalScope>();
+                let event = ConstellationMsg::SetDocumentState(global_scope.pipeline_id(), DocumentState::Idle);
+                global_scope.constellation_chan().send(event).unwrap();
             }
         }
 
@@ -1286,10 +1248,13 @@ impl Window {
         }
 
         let layer_id = self.layout_rpc.node_layer_id().layer_id;
-        let pipeline_id = self.id;
 
         let (send, recv) = ipc::channel::<Point2D<f32>>().unwrap();
-        self.constellation_chan.send(ConstellationMsg::GetScrollOffset(pipeline_id, layer_id, send)).unwrap();
+        let global_scope = self.upcast::<GlobalScope>();
+        global_scope
+            .constellation_chan()
+            .send(ConstellationMsg::GetScrollOffset(global_scope.pipeline_id(), layer_id, send))
+            .unwrap();
         recv.recv().unwrap_or(Point2D::zero())
     }
 
@@ -1364,13 +1329,13 @@ impl Window {
         let referrer_policy = referrer_policy.or(doc.get_referrer_policy());
 
         self.main_thread_script_chan().send(
-            MainThreadScriptMsg::Navigate(self.id,
+            MainThreadScriptMsg::Navigate(self.upcast::<GlobalScope>().pipeline_id(),
                 LoadData::new(url, referrer_policy, Some(doc.url().clone())),
                 replace)).unwrap();
     }
 
     pub fn handle_fire_timer(&self, timer_id: TimerEventId) {
-        self.timers.fire_timer(timer_id, self);
+        self.upcast::<GlobalScope>().fire_timer(timer_id);
         self.reflow(ReflowGoal::ForDisplay,
                     ReflowQueryType::NoQuery,
                     ReflowReason::Timer);
@@ -1396,44 +1361,10 @@ impl Window {
         (*self.Document().url()).clone()
     }
 
-    pub fn resource_threads(&self) -> &ResourceThreads {
-        &self.resource_threads
-    }
-
-    pub fn mem_profiler_chan(&self) -> &mem::ProfilerChan {
-        &self.mem_profiler_chan
-    }
-
-    pub fn time_profiler_chan(&self) -> &ProfilerChan {
-        &self.time_profiler_chan
-    }
-
-    pub fn devtools_chan(&self) -> Option<IpcSender<ScriptToDevtoolsControlMsg>> {
-        self.devtools_chan.clone()
-    }
-
     pub fn layout_chan(&self) -> &Sender<Msg> {
         &self.layout_chan
     }
 
-    pub fn constellation_chan(&self) -> &IpcSender<ConstellationMsg> {
-        &self.constellation_chan
-    }
-
-    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
-        &self.scheduler_chan
-    }
-
-    pub fn schedule_callback(&self, callback: OneshotTimerCallback, duration: MsDuration) -> OneshotTimerHandle {
-        self.timers.schedule_callback(callback,
-                                      duration,
-                                      TimerSource::FromWindow(self.id.clone()))
-    }
-
-    pub fn unschedule_callback(&self, handle: OneshotTimerHandle) {
-        self.timers.unschedule_callback(handle);
-    }
-
     pub fn windowproxy_handler(&self) -> WindowProxyHandler {
         WindowProxyHandler(self.dom_static.windowproxy_handler.0)
     }
@@ -1483,35 +1414,19 @@ impl Window {
         had_clip_rect
     }
 
-    pub fn set_devtools_wants_updates(&self, value: bool) {
-        self.devtools_wants_updates.set(value);
-    }
-
     // https://html.spec.whatwg.org/multipage/#accessing-other-browsing-contexts
     pub fn IndexedGetter(&self, _index: u32, _found: &mut bool) -> Option<Root<Window>> {
         None
     }
 
     pub fn thaw(&self) {
-        self.timers.resume();
+        self.upcast::<GlobalScope>().resume();
 
         // Push the document title to the compositor since we are
         // activating this document due to a navigation.
         self.Document().title_changed();
     }
 
-    pub fn freeze(&self) {
-        self.timers.suspend();
-    }
-
-    pub fn slow_down_timers(&self) {
-        self.timers.slow_down();
-    }
-
-    pub fn speed_up_timers(&self) {
-        self.timers.speed_up();
-    }
-
     pub fn need_emit_timeline_marker(&self, timeline_type: TimelineMarkerType) -> bool {
         let markers = self.devtools_markers.borrow();
         markers.contains(&timeline_type)
@@ -1580,10 +1495,9 @@ impl Window {
     /// in a top-level `Window` global.
     #[allow(unsafe_code)]
     pub unsafe fn global_is_mozbrowser(_: *mut JSContext, obj: HandleObject) -> bool {
-        match global_root_from_object(obj.get()).r() {
-            GlobalRef::Window(window) => window.is_mozbrowser(),
-            _ => false,
-        }
+        GlobalScope::from_object(obj.get())
+            .downcast::<Window>()
+            .map_or(false, |window| window.is_mozbrowser())
     }
 
     #[allow(unsafe_code)]
@@ -1629,7 +1543,16 @@ impl Window {
         };
         let current_time = time::get_time();
         let win = box Window {
-            eventtarget: EventTarget::new_inherited(),
+            globalscope:
+                GlobalScope::new_inherited(
+                    id,
+                    devtools_chan,
+                    mem_profiler_chan,
+                    time_profiler_chan,
+                    constellation_chan,
+                    scheduler_chan,
+                    resource_threads,
+                    timer_event_chan),
             script_chan: script_chan,
             dom_manipulation_task_source: dom_task_source,
             user_interaction_task_source: user_task_source,
@@ -1637,12 +1560,8 @@ impl Window {
             history_traversal_task_source: history_task_source,
             file_reading_task_source: file_task_source,
             image_cache_chan: image_cache_chan,
-            crypto: Default::default(),
             navigator: Default::default(),
             image_cache_thread: image_cache_thread,
-            mem_profiler_chan: mem_profiler_chan,
-            time_profiler_chan: time_profiler_chan,
-            devtools_chan: devtools_chan,
             history: Default::default(),
             browsing_context: Default::default(),
             performance: Default::default(),
@@ -1652,16 +1571,10 @@ impl Window {
             session_storage: Default::default(),
             local_storage: Default::default(),
             status: DOMRefCell::new(DOMString::new()),
-            scheduler_chan: scheduler_chan.clone(),
-            timers: OneshotTimers::new(timer_event_chan, scheduler_chan),
-            next_worker_id: Cell::new(WorkerId(0)),
-            id: id,
             parent_info: parent_info,
             dom_static: GlobalStaticData::new(),
             js_runtime: DOMRefCell::new(Some(runtime.clone())),
-            resource_threads: resource_threads,
             bluetooth_thread: bluetooth_thread,
-            constellation_chan: constellation_chan,
             page_clip_rect: Cell::new(max_rect()),
             fragment_name: DOMRefCell::new(None),
             resize_event: Cell::new(None),
@@ -1675,54 +1588,14 @@ impl Window {
 
             devtools_marker_sender: DOMRefCell::new(None),
             devtools_markers: DOMRefCell::new(HashSet::new()),
-            devtools_wants_updates: Cell::new(false),
             webdriver_script_chan: DOMRefCell::new(None),
             ignore_further_async_events: Arc::new(AtomicBool::new(false)),
             error_reporter: error_reporter,
             scroll_offsets: DOMRefCell::new(HashMap::new()),
-            in_error_reporting_mode: Cell::new(false),
-            console_timers: TimerSet::new(),
         };
 
         WindowBinding::Wrap(runtime.cx(), win)
     }
-
-    pub fn console_timers(&self) -> &TimerSet {
-        &self.console_timers
-    }
-
-    pub fn live_devtools_updates(&self) -> bool {
-        return self.devtools_wants_updates.get();
-    }
-
-    /// https://html.spec.whatwg.org/multipage/#report-the-error
-    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
-        // Step 1.
-        if self.in_error_reporting_mode.get() {
-            return;
-        }
-
-        // Step 2.
-        self.in_error_reporting_mode.set(true);
-
-        // Steps 3-12.
-        // FIXME(#13195): muted errors.
-        let event = ErrorEvent::new(GlobalRef::Window(self),
-                                    atom!("error"),
-                                    EventBubbles::DoesNotBubble,
-                                    EventCancelable::Cancelable,
-                                    error_info.message.into(),
-                                    error_info.filename.into(),
-                                    error_info.lineno,
-                                    error_info.column,
-                                    value);
-
-        // Step 13.
-        event.upcast::<Event>().fire(self.upcast::<EventTarget>());
-
-        // Step 14.
-        self.in_error_reporting_mode.set(false);
-    }
 }
 
 fn should_move_clip_rect(clip_rect: Rect<Au>, new_viewport: Rect<f32>) -> bool {
@@ -1826,12 +1699,12 @@ impl Runnable for PostMessageHandler {
         let _ac = JSAutoCompartment::new(cx, globalhandle.get());
 
         rooted!(in(cx) let mut message = UndefinedValue());
-        this.message.read(GlobalRef::Window(&*window), message.handle_mut());
+        this.message.read(window.upcast(), message.handle_mut());
 
         // Step 11-12.
         // TODO(#12719): set the other attributes.
         MessageEvent::dispatch_jsval(window.upcast(),
-                                     GlobalRef::Window(&*window),
+                                     window.upcast(),
                                      message.handle());
     }
 }
diff --git a/components/script/dom/worker.rs b/components/script/dom/worker.rs
index fb6b170ab1d..42ba8bb8e08 100644
--- a/components/script/dom/worker.rs
+++ b/components/script/dom/worker.rs
@@ -9,7 +9,6 @@ use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
 use dom::bindings::codegen::Bindings::WorkerBinding;
 use dom::bindings::codegen::Bindings::WorkerBinding::WorkerMethods;
 use dom::bindings::error::{Error, ErrorResult, Fallible, ErrorInfo};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
@@ -21,6 +20,7 @@ use dom::errorevent::ErrorEvent;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventdispatcher::EventStatus;
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::messageevent::MessageEvent;
 use dom::workerglobalscope::prepare_workerscope_init;
 use ipc_channel::ipc;
@@ -61,7 +61,7 @@ impl Worker {
         }
     }
 
-    pub fn new(global: GlobalRef,
+    pub fn new(global: &GlobalScope,
                sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
                closing: Arc<AtomicBool>) -> Root<Worker> {
         reflect_dom_object(box Worker::new_inherited(sender, closing),
@@ -71,7 +71,7 @@ impl Worker {
 
     // https://html.spec.whatwg.org/multipage/#dom-worker
     #[allow(unsafe_code)]
-    pub fn Constructor(global: GlobalRef, script_url: DOMString) -> Fallible<Root<Worker>> {
+    pub fn Constructor(global: &GlobalScope, script_url: DOMString) -> Fallible<Root<Worker>> {
         // Step 2-4.
         let worker_url = match global.api_base_url().join(&script_url) {
             Ok(url) => url,
@@ -128,12 +128,12 @@ impl Worker {
             return;
         }
 
-        let global = worker.r().global();
+        let global = worker.global();
         let target = worker.upcast();
-        let _ac = JSAutoCompartment::new(global.r().get_cx(), target.reflector().get_jsobject().get());
-        rooted!(in(global.r().get_cx()) let mut message = UndefinedValue());
-        data.read(global.r(), message.handle_mut());
-        MessageEvent::dispatch_jsval(target, global.r(), message.handle());
+        let _ac = JSAutoCompartment::new(global.get_cx(), target.reflector().get_jsobject().get());
+        rooted!(in(global.get_cx()) let mut message = UndefinedValue());
+        data.read(&global, message.handle_mut());
+        MessageEvent::dispatch_jsval(target, &global, message.handle());
     }
 
     pub fn dispatch_simple_error(address: TrustedWorkerAddress) {
@@ -144,7 +144,7 @@ impl Worker {
     #[allow(unsafe_code)]
     fn dispatch_error(&self, error_info: ErrorInfo) {
         let global = self.global();
-        let event = ErrorEvent::new(global.r(),
+        let event = ErrorEvent::new(&global,
                                     atom!("error"),
                                     EventBubbles::DoesNotBubble,
                                     EventCancelable::Cancelable,
@@ -159,7 +159,7 @@ impl Worker {
             return;
         }
 
-        global.r().report_an_error(error_info, unsafe { NullHandleValue });
+        global.report_an_error(error_info, unsafe { NullHandleValue });
     }
 }
 
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index 9b976c5a31d..8cd09b3fdbe 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -2,26 +2,21 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use devtools_traits::{DevtoolScriptControlMsg, ScriptToDevtoolsControlMsg, WorkerId};
+use devtools_traits::{DevtoolScriptControlMsg, WorkerId};
 use dom::bindings::codegen::Bindings::EventHandlerBinding::OnErrorEventHandlerNonNull;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::codegen::Bindings::RequestBinding::RequestInit;
 use dom::bindings::codegen::Bindings::WorkerGlobalScopeBinding::WorkerGlobalScopeMethods;
 use dom::bindings::codegen::UnionTypes::RequestOrUSVString;
-use dom::bindings::error::{Error, ErrorInfo, ErrorResult, Fallible, report_pending_exception};
-use dom::bindings::global::{GlobalRef, GlobalRoot};
+use dom::bindings::error::{Error, ErrorResult, Fallible, report_pending_exception};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::DOMString;
-use dom::console::TimerSet;
 use dom::crypto::Crypto;
 use dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
-use dom::errorevent::ErrorEvent;
-use dom::event::{Event, EventBubbles, EventCancelable};
-use dom::eventdispatcher::EventStatus;
-use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use dom::serviceworkerglobalscope::ServiceWorkerGlobalScope;
 use dom::window::{base64_atob, base64_btoa};
@@ -34,15 +29,12 @@ use js::jsval::UndefinedValue;
 use js::rust::Runtime;
 use msg::constellation_msg::{PipelineId, ReferrerPolicy};
 use net_traits::{IpcSend, LoadOrigin};
-use net_traits::{LoadContext, ResourceThreads, load_whole_resource};
-use profile_traits::{mem, time};
+use net_traits::{LoadContext, load_whole_resource};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, maybe_take_panic_result};
 use script_runtime::{ScriptThreadEventCategory, PromiseJobQueue, EnqueuedPromiseCallback};
 use script_thread::{Runnable, RunnableWrapper};
-use script_traits::{MsDuration, TimerEvent, TimerEventId, TimerEventRequest, TimerSource};
-use script_traits::ScriptMsg as ConstellationMsg;
+use script_traits::{TimerEvent, TimerEventId};
 use script_traits::WorkerGlobalScopeInit;
-use std::cell::Cell;
 use std::default::Default;
 use std::panic;
 use std::rc::Rc;
@@ -50,26 +42,20 @@ use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::Receiver;
 use task_source::file_reading::FileReadingTaskSource;
-use timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle, OneshotTimers, TimerCallback};
+use timers::{IsInterval, TimerCallback};
 use url::Url;
 
-#[derive(Copy, Clone, PartialEq)]
-pub enum WorkerGlobalScopeTypeId {
-    DedicatedWorkerGlobalScope,
-}
-
-pub fn prepare_workerscope_init(global: GlobalRef,
+pub fn prepare_workerscope_init(global: &GlobalScope,
                                 devtools_sender: Option<IpcSender<DevtoolScriptControlMsg>>) -> WorkerGlobalScopeInit {
-    let worker_id = global.get_next_worker_id();
     let init = WorkerGlobalScopeInit {
-            resource_threads: global.resource_threads(),
+            resource_threads: global.resource_threads().clone(),
             mem_profiler_chan: global.mem_profiler_chan().clone(),
-            to_devtools_sender: global.devtools_chan(),
+            to_devtools_sender: global.devtools_chan().cloned(),
             time_profiler_chan: global.time_profiler_chan().clone(),
             from_devtools_sender: devtools_sender,
             constellation_chan: global.constellation_chan().clone(),
             scheduler_chan: global.scheduler_chan().clone(),
-            worker_id: worker_id,
+            worker_id: global.get_next_worker_id(),
             pipeline_id: global.pipeline_id(),
         };
 
@@ -79,28 +65,16 @@ pub fn prepare_workerscope_init(global: GlobalRef,
 // https://html.spec.whatwg.org/multipage/#the-workerglobalscope-common-interface
 #[dom_struct]
 pub struct WorkerGlobalScope {
-    eventtarget: EventTarget,
+    globalscope: GlobalScope,
+
     worker_id: WorkerId,
-    pipeline_id: PipelineId,
     worker_url: Url,
     #[ignore_heap_size_of = "Arc"]
     closing: Option<Arc<AtomicBool>>,
     #[ignore_heap_size_of = "Defined in js"]
     runtime: Runtime,
-    next_worker_id: Cell<WorkerId>,
-    #[ignore_heap_size_of = "Defined in std"]
-    resource_threads: ResourceThreads,
     location: MutNullableHeap<JS<WorkerLocation>>,
     navigator: MutNullableHeap<JS<WorkerNavigator>>,
-    crypto: MutNullableHeap<JS<Crypto>>,
-    timers: OneshotTimers,
-
-    #[ignore_heap_size_of = "Defined in std"]
-    mem_profiler_chan: mem::ProfilerChan,
-    #[ignore_heap_size_of = "Defined in std"]
-    time_profiler_chan: time::ProfilerChan,
-    #[ignore_heap_size_of = "Defined in ipc-channel"]
-    to_devtools_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
 
     #[ignore_heap_size_of = "Defined in ipc-channel"]
     /// Optional `IpcSender` for sending the `DevtoolScriptControlMsg`
@@ -112,23 +86,7 @@ pub struct WorkerGlobalScope {
     /// `IpcSender` doesn't exist
     from_devtools_receiver: Receiver<DevtoolScriptControlMsg>,
 
-    /// A flag to indicate whether the developer tools has requested live updates
-    /// from the worker
-    devtools_wants_updates: Cell<bool>,
-
-    #[ignore_heap_size_of = "Defined in std"]
-    constellation_chan: IpcSender<ConstellationMsg>,
-
-    #[ignore_heap_size_of = "Defined in std"]
-    scheduler_chan: IpcSender<TimerEventRequest>,
-
-    /// Timers used by the Console API.
-    console_timers: TimerSet,
-
     promise_job_queue: PromiseJobQueue,
-
-    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
-    in_error_reporting_mode: Cell<bool>
 }
 
 impl WorkerGlobalScope {
@@ -140,48 +98,28 @@ impl WorkerGlobalScope {
                          closing: Option<Arc<AtomicBool>>)
                          -> WorkerGlobalScope {
         WorkerGlobalScope {
-            eventtarget: EventTarget::new_inherited(),
-            next_worker_id: Cell::new(WorkerId(0)),
+            globalscope:
+                GlobalScope::new_inherited(
+                    init.pipeline_id,
+                    init.to_devtools_sender,
+                    init.mem_profiler_chan,
+                    init.time_profiler_chan,
+                    init.constellation_chan,
+                    init.scheduler_chan,
+                    init.resource_threads,
+                    timer_event_chan),
             worker_id: init.worker_id,
-            pipeline_id: init.pipeline_id,
             worker_url: worker_url,
             closing: closing,
             runtime: runtime,
-            resource_threads: init.resource_threads,
             location: Default::default(),
             navigator: Default::default(),
-            crypto: Default::default(),
-            timers: OneshotTimers::new(timer_event_chan, init.scheduler_chan.clone()),
-            mem_profiler_chan: init.mem_profiler_chan,
-            time_profiler_chan: init.time_profiler_chan,
-            to_devtools_sender: init.to_devtools_sender,
             from_devtools_sender: init.from_devtools_sender,
             from_devtools_receiver: from_devtools_receiver,
-            devtools_wants_updates: Cell::new(false),
-            constellation_chan: init.constellation_chan,
-            scheduler_chan: init.scheduler_chan,
-            console_timers: TimerSet::new(),
             promise_job_queue: PromiseJobQueue::new(),
-            in_error_reporting_mode: Default::default(),
         }
     }
 
-    pub fn console_timers(&self) -> &TimerSet {
-        &self.console_timers
-    }
-
-    pub fn mem_profiler_chan(&self) -> &mem::ProfilerChan {
-        &self.mem_profiler_chan
-    }
-
-    pub fn time_profiler_chan(&self) -> &time::ProfilerChan {
-        &self.time_profiler_chan
-    }
-
-    pub fn devtools_chan(&self) -> Option<IpcSender<ScriptToDevtoolsControlMsg>> {
-        self.to_devtools_sender.clone()
-    }
-
     pub fn from_devtools_sender(&self) -> Option<IpcSender<DevtoolScriptControlMsg>> {
         self.from_devtools_sender.clone()
     }
@@ -190,24 +128,6 @@ impl WorkerGlobalScope {
         &self.from_devtools_receiver
     }
 
-    pub fn constellation_chan(&self) -> &IpcSender<ConstellationMsg> {
-        &self.constellation_chan
-    }
-
-    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
-        &self.scheduler_chan
-    }
-
-    pub fn schedule_callback(&self, callback: OneshotTimerCallback, duration: MsDuration) -> OneshotTimerHandle {
-        self.timers.schedule_callback(callback,
-                                      duration,
-                                      TimerSource::FromWorker)
-    }
-
-    pub fn unschedule_callback(&self, handle: OneshotTimerHandle) {
-        self.timers.unschedule_callback(handle);
-    }
-
     pub fn runtime(&self) -> *mut JSRuntime {
         self.runtime.rt()
     }
@@ -224,10 +144,6 @@ impl WorkerGlobalScope {
         }
     }
 
-    pub fn resource_threads(&self) -> &ResourceThreads {
-        &self.resource_threads
-    }
-
     pub fn get_url(&self) -> &Url {
         &self.worker_url
     }
@@ -236,21 +152,14 @@ impl WorkerGlobalScope {
         self.worker_id.clone()
     }
 
-    pub fn get_next_worker_id(&self) -> WorkerId {
-        let worker_id = self.next_worker_id.get();
-        let WorkerId(id_num) = worker_id;
-        self.next_worker_id.set(WorkerId(id_num + 1));
-        worker_id
-    }
-
     pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
         RunnableWrapper {
-            cancelled: self.closing.clone().unwrap(),
+            cancelled: self.closing.clone(),
         }
     }
 
     pub fn enqueue_promise_job(&self, job: EnqueuedPromiseCallback) {
-        self.promise_job_queue.enqueue(job, GlobalRef::Worker(self));
+        self.promise_job_queue.enqueue(job, self.upcast());
     }
 
     pub fn flush_promise_jobs(&self) {
@@ -263,8 +172,9 @@ impl WorkerGlobalScope {
 
     fn do_flush_promise_jobs(&self) {
         self.promise_job_queue.flush_promise_jobs(|id| {
-            assert_eq!(self.pipeline_id(), id);
-            Some(GlobalRoot::Worker(Root::from_ref(self)))
+            let global = self.upcast::<GlobalScope>();
+            assert_eq!(global.pipeline_id(), id);
+            Some(Root::from_ref(global))
         });
     }
 }
@@ -277,7 +187,7 @@ impl LoadOrigin for WorkerGlobalScope {
         None
     }
     fn pipeline_id(&self) -> Option<PipelineId> {
-        Some(self.pipeline_id())
+        Some(self.upcast::<GlobalScope>().pipeline_id())
     }
 }
 
@@ -310,8 +220,9 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
 
         rooted!(in(self.runtime.cx()) let mut rval = UndefinedValue());
         for url in urls {
+            let global_scope = self.upcast::<GlobalScope>();
             let (url, source) = match load_whole_resource(LoadContext::Script,
-                                                          &self.resource_threads.sender(),
+                                                          &global_scope.resource_threads().sender(),
                                                           url,
                                                           self) {
                 Err(_) => return Err(Error::Network),
@@ -346,7 +257,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
 
     // https://html.spec.whatwg.org/multipage/#dfn-Crypto
     fn Crypto(&self) -> Root<Crypto> {
-        self.crypto.or_init(|| Crypto::new(GlobalRef::Worker(self)))
+        self.upcast::<GlobalScope>().crypto()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowbase64-btoa
@@ -359,49 +270,45 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
         base64_atob(atob)
     }
 
-    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
+    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout
     fn SetTimeout(&self, _cx: *mut JSContext, callback: Rc<Function>, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Worker(self),
-                                            TimerCallback::FunctionTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::NonInterval,
-                                            TimerSource::FromWorker)
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::FunctionTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::NonInterval)
     }
 
-    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
+    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout
     fn SetTimeout_(&self, _cx: *mut JSContext, callback: DOMString, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Worker(self),
-                                            TimerCallback::StringTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::NonInterval,
-                                            TimerSource::FromWorker)
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::StringTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::NonInterval)
     }
 
-    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
+    // https://html.spec.whatwg.org/multipage/#dom-windowtimers-cleartimeout
     fn ClearTimeout(&self, handle: i32) {
-        self.timers.clear_timeout_or_interval(GlobalRef::Worker(self), handle);
+        self.upcast::<GlobalScope>().clear_timeout_or_interval(handle);
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
     fn SetInterval(&self, _cx: *mut JSContext, callback: Rc<Function>, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Worker(self),
-                                            TimerCallback::FunctionTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::Interval,
-                                            TimerSource::FromWorker)
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::FunctionTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::Interval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
     fn SetInterval_(&self, _cx: *mut JSContext, callback: DOMString, timeout: i32, args: Vec<HandleValue>) -> i32 {
-        self.timers.set_timeout_or_interval(GlobalRef::Worker(self),
-                                            TimerCallback::StringTimerCallback(callback),
-                                            args,
-                                            timeout,
-                                            IsInterval::Interval,
-                                            TimerSource::FromWorker)
+        self.upcast::<GlobalScope>().set_timeout_or_interval(
+            TimerCallback::StringTimerCallback(callback),
+            args,
+            timeout,
+            IsInterval::Interval)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
@@ -412,7 +319,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
     #[allow(unrooted_must_root)]
     // https://fetch.spec.whatwg.org/#fetch-method
     fn Fetch(&self, input: RequestOrUSVString, init: &RequestInit) -> Rc<Promise> {
-        fetch::Fetch(self.global().r(), input, init)
+        fetch::Fetch(self.upcast(), input, init)
     }
 }
 
@@ -457,10 +364,6 @@ impl WorkerGlobalScope {
         FileReadingTaskSource(self.script_chan())
     }
 
-    pub fn pipeline_id(&self) -> PipelineId {
-        self.pipeline_id
-    }
-
     pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
         let dedicated = self.downcast::<DedicatedWorkerGlobalScope>();
         if let Some(dedicated) = dedicated {
@@ -483,11 +386,7 @@ impl WorkerGlobalScope {
     }
 
     pub fn handle_fire_timer(&self, timer_id: TimerEventId) {
-        self.timers.fire_timer(timer_id, self);
-    }
-
-    pub fn set_devtools_wants_updates(&self, value: bool) {
-        self.devtools_wants_updates.set(value);
+        self.upcast::<GlobalScope>().fire_timer(timer_id);
     }
 
     pub fn close(&self) {
@@ -495,42 +394,6 @@ impl WorkerGlobalScope {
             closing.store(true, Ordering::SeqCst);
         }
     }
-
-    /// https://html.spec.whatwg.org/multipage/#report-the-error
-    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
-        // Step 1.
-        if self.in_error_reporting_mode.get() {
-            return;
-        }
-
-        // Step 2.
-        self.in_error_reporting_mode.set(true);
-
-        // Steps 3-12.
-        // FIXME(#13195): muted errors.
-        let event = ErrorEvent::new(GlobalRef::Worker(self),
-                                    atom!("error"),
-                                    EventBubbles::DoesNotBubble,
-                                    EventCancelable::Cancelable,
-                                    error_info.message.as_str().into(),
-                                    error_info.filename.as_str().into(),
-                                    error_info.lineno,
-                                    error_info.column,
-                                    value);
-
-        // Step 13.
-        let event_status = event.upcast::<Event>().fire(self.upcast::<EventTarget>());
-
-        // Step 15
-        if event_status == EventStatus::NotCanceled {
-            if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
-                dedicated.forward_error_to_worker_object(error_info);
-            }
-        }
-
-        // Step 14
-        self.in_error_reporting_mode.set(false);
-    }
 }
 
 struct FlushPromiseJobs {
diff --git a/components/script/dom/workerlocation.rs b/components/script/dom/workerlocation.rs
index a037f7737a8..287a803a612 100644
--- a/components/script/dom/workerlocation.rs
+++ b/components/script/dom/workerlocation.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::WorkerLocationBinding;
 use dom::bindings::codegen::Bindings::WorkerLocationBinding::WorkerLocationMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
@@ -29,7 +28,7 @@ impl WorkerLocation {
 
     pub fn new(global: &WorkerGlobalScope, url: Url) -> Root<WorkerLocation> {
         reflect_dom_object(box WorkerLocation::new_inherited(url),
-                           GlobalRef::Worker(global),
+                           global,
                            WorkerLocationBinding::Wrap)
     }
 }
diff --git a/components/script/dom/workernavigator.rs b/components/script/dom/workernavigator.rs
index 1114a91a169..f6cd521634d 100644
--- a/components/script/dom/workernavigator.rs
+++ b/components/script/dom/workernavigator.rs
@@ -4,7 +4,6 @@
 
 use dom::bindings::codegen::Bindings::WorkerNavigatorBinding;
 use dom::bindings::codegen::Bindings::WorkerNavigatorBinding::WorkerNavigatorMethods;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
@@ -26,7 +25,7 @@ impl WorkerNavigator {
 
     pub fn new(global: &WorkerGlobalScope) -> Root<WorkerNavigator> {
         reflect_dom_object(box WorkerNavigator::new_inherited(),
-                           GlobalRef::Worker(global),
+                           global,
                            WorkerNavigatorBinding::Wrap)
     }
 }
diff --git a/components/script/dom/xmldocument.rs b/components/script/dom/xmldocument.rs
index 1a00f67b80c..6fb57ea52fd 100644
--- a/components/script/dom/xmldocument.rs
+++ b/components/script/dom/xmldocument.rs
@@ -6,7 +6,6 @@ use core::nonzero::NonZero;
 use document_loader::DocumentLoader;
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::XMLDocumentBinding::{self, XMLDocumentMethods};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
@@ -66,7 +65,7 @@ impl XMLDocument {
                                            last_modified,
                                            source,
                                            doc_loader),
-            GlobalRef::Window(window),
+            window,
             XMLDocumentBinding::Wrap);
         {
             let node = doc.upcast::<Node>();
diff --git a/components/script/dom/xmlhttprequest.rs b/components/script/dom/xmlhttprequest.rs
index caebbddd09e..cd2cd37c476 100644
--- a/components/script/dom/xmlhttprequest.rs
+++ b/components/script/dom/xmlhttprequest.rs
@@ -13,7 +13,6 @@ use dom::bindings::codegen::Bindings::XMLHttpRequestBinding::XMLHttpRequestMetho
 use dom::bindings::codegen::Bindings::XMLHttpRequestBinding::XMLHttpRequestResponseType;
 use dom::bindings::conversions::ToJSValConvertible;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
-use dom::bindings::global::{GlobalRef, GlobalRoot};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutHeapJSVal, MutNullableHeap};
 use dom::bindings::js::{Root, RootedReference};
@@ -25,9 +24,12 @@ use dom::document::{Document, IsHTMLDocument};
 use dom::document::DocumentSource;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
+use dom::globalscope::GlobalScope;
 use dom::headers::is_forbidden_header_name;
 use dom::htmlformelement::{encode_multipart_form_data, generate_boundary};
 use dom::progressevent::ProgressEvent;
+use dom::window::Window;
+use dom::workerglobalscope::WorkerGlobalScope;
 use dom::xmlhttprequesteventtarget::XMLHttpRequestEventTarget;
 use dom::xmlhttprequestupload::XMLHttpRequestUpload;
 use encoding::all::UTF_8;
@@ -153,9 +155,9 @@ pub struct XMLHttpRequest {
 }
 
 impl XMLHttpRequest {
-    fn new_inherited(global: GlobalRef) -> XMLHttpRequest {
+    fn new_inherited(global: &GlobalScope) -> XMLHttpRequest {
         //TODO - update this when referrer policy implemented for workers
-        let (referrer_url, referrer_policy) = if let GlobalRef::Window(window) = global {
+        let (referrer_url, referrer_policy) = if let Some(window) = global.downcast::<Window>() {
             let document = window.Document();
             (Some(document.url().clone()), document.get_referrer_policy())
         } else {
@@ -196,22 +198,19 @@ impl XMLHttpRequest {
             referrer_policy: referrer_policy,
         }
     }
-    pub fn new(global: GlobalRef) -> Root<XMLHttpRequest> {
+    pub fn new(global: &GlobalScope) -> Root<XMLHttpRequest> {
         reflect_dom_object(box XMLHttpRequest::new_inherited(global),
                            global,
                            XMLHttpRequestBinding::Wrap)
     }
 
     // https://xhr.spec.whatwg.org/#constructors
-    pub fn Constructor(global: GlobalRef) -> Fallible<Root<XMLHttpRequest>> {
+    pub fn Constructor(global: &GlobalScope) -> Fallible<Root<XMLHttpRequest>> {
         Ok(XMLHttpRequest::new(global))
     }
 
     fn sync_in_window(&self) -> bool {
-        match self.global() {
-            GlobalRoot::Window(_) if self.sync.get() => true,
-            _ => false
-        }
+        self.sync.get() && self.global().is::<Window>()
     }
 
     fn initiate_async_xhr(context: Arc<Mutex<XHRContext>>,
@@ -283,8 +282,7 @@ impl LoadOrigin for XMLHttpRequest {
     }
 
     fn pipeline_id(&self) -> Option<PipelineId> {
-        let global = self.global();
-        Some(global.r().pipeline_id())
+        Some(self.global().pipeline_id())
     }
 }
 
@@ -307,11 +305,10 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
     fn Open_(&self, method: ByteString, url: USVString, async: bool,
              username: Option<USVString>, password: Option<USVString>) -> ErrorResult {
         // Step 1
-        match self.global() {
-            GlobalRoot::Window(ref window) => {
-                if !window.Document().r().is_fully_active() { return Err(Error::InvalidState); }
+        if let Some(window) = Root::downcast::<Window>(self.global()) {
+            if !window.Document().r().is_fully_active() {
+                return Err(Error::InvalidState);
             }
-            _ => {}
         }
 
         // Step 5
@@ -342,7 +339,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
                 }
 
                 // Step 2
-                let base = self.global().r().api_base_url();
+                let base = self.global().api_base_url();
                 // Step 6
                 let mut parsed_url = match base.join(&url.0) {
                     Ok(parsed) => parsed,
@@ -574,7 +571,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
             // preference is enabled, we allow bypassing the CORS check.
             // This is a temporary measure until we figure out Servo privilege
             // story. See https://github.com/servo/servo/issues/9582
-            if let GlobalRoot::Window(win) = self.global() {
+            if let Some(win) = Root::downcast::<Window>(self.global()) {
                 let is_root_pipeline = win.parent_info().is_none();
                 is_root_pipeline && PREFS.is_mozbrowser_enabled()
             } else {
@@ -597,7 +594,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
             use_cors_preflight: has_handlers,
             credentials_mode: credentials_mode,
             use_url_credentials: use_url_credentials,
-            origin: self.global().r().get_url(),
+            origin: self.global().get_url(),
             referrer_url: self.referrer_url.clone(),
             referrer_policy: self.referrer_policy.clone(),
             pipeline_id: self.pipeline_id(),
@@ -652,7 +649,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
 
         self.fetch_time.set(time::now().to_timespec().sec);
 
-        let rv = self.fetch(request, self.global().r());
+        let rv = self.fetch(request, &self.global());
         // Step 10
         if self.sync.get() {
             return rv;
@@ -743,9 +740,8 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
     // https://xhr.spec.whatwg.org/#the-responsetype-attribute
     fn SetResponseType(&self, response_type: XMLHttpRequestResponseType) -> ErrorResult {
         // Step 1
-        match self.global() {
-            GlobalRoot::Worker(_) if response_type == XMLHttpRequestResponseType::Document => return Ok(()),
-            _ => {}
+        if self.global().is::<WorkerGlobalScope>() && response_type == XMLHttpRequestResponseType::Document {
+            return Ok(());
         }
         match self.ready_state.get() {
             // Step 2
@@ -828,7 +824,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
     fn GetResponseXML(&self) -> Fallible<Option<Root<Document>>> {
         // TODO(#2823): Until [Exposed] is implemented, this attribute needs to return null
         //              explicitly in the worker scope.
-        if let GlobalRoot::Worker(_) = self.global() {
+        if self.global().is::<WorkerGlobalScope>() {
             return Ok(None);
         }
 
@@ -859,8 +855,7 @@ impl XMLHttpRequest {
     fn change_ready_state(&self, rs: XMLHttpRequestState) {
         assert!(self.ready_state.get() != rs);
         self.ready_state.set(rs);
-        let global = self.global();
-        let event = Event::new(global.r(),
+        let event = Event::new(&self.global(),
                                atom!("readystatechange"),
                                EventBubbles::DoesNotBubble,
                                EventCancelable::Cancelable);
@@ -975,9 +970,8 @@ impl XMLHttpRequest {
                     if self.ready_state.get() == XMLHttpRequestState::HeadersReceived {
                         self.ready_state.set(XMLHttpRequestState::Loading);
                     }
-                    let global = self.global();
                     let event = Event::new(
-                        global.r(),
+                        &self.global(),
                         atom!("readystatechange"),
                         EventBubbles::DoesNotBubble,
                         EventCancelable::Cancelable);
@@ -1049,8 +1043,7 @@ impl XMLHttpRequest {
     }
 
     fn dispatch_progress_event(&self, upload: bool, type_: Atom, loaded: u64, total: Option<u64>) {
-        let global = self.global();
-        let progressevent = ProgressEvent::new(global.r(),
+        let progressevent = ProgressEvent::new(&self.global(),
                                                type_,
                                                EventBubbles::DoesNotBubble,
                                                EventCancelable::NotCancelable,
@@ -1083,15 +1076,14 @@ impl XMLHttpRequest {
             xhr: Trusted::new(self),
             generation_id: self.generation_id.get(),
         });
-        let global = self.global();
         let duration = Length::new(duration_ms as u64);
-        *self.timeout_cancel.borrow_mut() = Some(global.r().schedule_callback(callback, duration));
+        *self.timeout_cancel.borrow_mut() =
+            Some(self.global().schedule_callback(callback, duration));
     }
 
     fn cancel_timeout(&self) {
         if let Some(handle) = self.timeout_cancel.borrow_mut().take() {
-            let global = self.global();
-            global.r().unschedule_callback(handle);
+            self.global().unschedule_callback(handle);
         }
     }
 
@@ -1118,7 +1110,7 @@ impl XMLHttpRequest {
 
         // Step 3, 4
         let bytes = self.response.borrow().to_vec();
-        let blob = Blob::new(self.global().r(), BlobImpl::new_from_bytes(bytes), mime);
+        let blob = Blob::new(&self.global(), BlobImpl::new_from_bytes(bytes), mime);
         self.response_blob.set(Some(blob.r()));
         blob
     }
@@ -1204,18 +1196,19 @@ impl XMLHttpRequest {
     fn document_text_html(&self) -> Root<Document>{
         let charset = self.final_charset().unwrap_or(UTF_8);
         let wr = self.global();
-        let wr = wr.r();
         let decoded = charset.decode(&self.response.borrow(), DecoderTrap::Replace).unwrap();
         let document = self.new_doc(IsHTMLDocument::HTMLDocument);
         // TODO: Disable scripting while parsing
-        parse_html(document.r(), DOMString::from(decoded), wr.get_url(), ParseContext::Owner(Some(wr.pipeline_id())));
+        parse_html(document.r(),
+                   DOMString::from(decoded),
+                   wr.get_url(),
+                   ParseContext::Owner(Some(wr.pipeline_id())));
         document
     }
 
     fn handle_xml(&self) -> Root<Document> {
         let charset = self.final_charset().unwrap_or(UTF_8);
         let wr = self.global();
-        let wr = wr.r();
         let decoded = charset.decode(&self.response.borrow(), DecoderTrap::Replace).unwrap();
         let document = self.new_doc(IsHTMLDocument::NonHTMLDocument);
         // TODO: Disable scripting while parsing
@@ -1228,12 +1221,11 @@ impl XMLHttpRequest {
 
     fn new_doc(&self, is_html_document: IsHTMLDocument) -> Root<Document> {
         let wr = self.global();
-        let wr = wr.r();
         let win = wr.as_window();
         let doc = win.Document();
         let doc = doc.r();
         let docloader = DocumentLoader::new(&*doc.loader());
-        let base = self.global().r().get_url();
+        let base = wr.get_url();
         let parsed_url = match base.join(&self.ResponseURL().0) {
             Ok(parsed) => Some(parsed),
             Err(_) => None // Step 7
@@ -1292,7 +1284,7 @@ impl XMLHttpRequest {
 
     fn fetch(&self,
               init: RequestInit,
-              global: GlobalRef) -> ErrorResult {
+              global: &GlobalScope) -> ErrorResult {
         let xhr = Trusted::new(self);
 
         let context = Arc::new(Mutex::new(XHRContext {
diff --git a/components/script/dom/xmlhttprequestupload.rs b/components/script/dom/xmlhttprequestupload.rs
index 900548f2e05..6c53fe15eca 100644
--- a/components/script/dom/xmlhttprequestupload.rs
+++ b/components/script/dom/xmlhttprequestupload.rs
@@ -3,9 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::Bindings::XMLHttpRequestUploadBinding;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
+use dom::globalscope::GlobalScope;
 use dom::xmlhttprequesteventtarget::XMLHttpRequestEventTarget;
 
 #[dom_struct]
@@ -19,7 +19,7 @@ impl XMLHttpRequestUpload {
             eventtarget: XMLHttpRequestEventTarget::new_inherited(),
         }
     }
-    pub fn new(global: GlobalRef) -> Root<XMLHttpRequestUpload> {
+    pub fn new(global: &GlobalScope) -> Root<XMLHttpRequestUpload> {
         reflect_dom_object(box XMLHttpRequestUpload::new_inherited(),
                            global,
                            XMLHttpRequestUploadBinding::Wrap)
diff --git a/components/script/fetch.rs b/components/script/fetch.rs
index 634439c7c7d..6db6c5e4202 100644
--- a/components/script/fetch.rs
+++ b/components/script/fetch.rs
@@ -7,10 +7,10 @@ use dom::bindings::codegen::Bindings::ResponseBinding::ResponseBinding::Response
 use dom::bindings::codegen::Bindings::ResponseBinding::ResponseType as DOMResponseType;
 use dom::bindings::codegen::UnionTypes::RequestOrUSVString;
 use dom::bindings::error::Error;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::refcounted::{Trusted, TrustedPromise};
 use dom::bindings::reflector::Reflectable;
+use dom::globalscope::GlobalScope;
 use dom::headers::Guard;
 use dom::promise::Promise;
 use dom::request::Request;
@@ -66,7 +66,7 @@ fn request_init_from_request(request: NetTraitsRequest) -> NetTraitsRequestInit
 
 // https://fetch.spec.whatwg.org/#fetch-method
 #[allow(unrooted_must_root)]
-pub fn Fetch(global: GlobalRef, input: RequestOrUSVString, init: &RequestInit) -> Rc<Promise> {
+pub fn Fetch(global: &GlobalScope, input: RequestOrUSVString, init: &RequestInit) -> Rc<Promise> {
     let core_resource_thread = global.core_resource_thread();
 
     // Step 1
@@ -76,7 +76,7 @@ pub fn Fetch(global: GlobalRef, input: RequestOrUSVString, init: &RequestInit) -
     // Step 2
     let request = match Request::Constructor(global, input, init) {
         Err(e) => {
-            promise.reject_error(promise.global().r().get_cx(), e);
+            promise.reject_error(promise.global().get_cx(), e);
             return promise;
         },
         Ok(r) => r.get_request(),
@@ -124,13 +124,13 @@ impl FetchResponseListener for FetchContext {
 
         // JSAutoCompartment needs to be manually made.
         // Otherwise, Servo will crash.
-        let promise_cx = promise.global().r().get_cx();
+        let promise_cx = promise.global().get_cx();
         let _ac = JSAutoCompartment::new(promise_cx, promise.reflector().get_jsobject().get());
         match fetch_metadata {
             // Step 4.1
             Err(_) => {
                 promise.reject_error(
-                    promise.global().r().get_cx(),
+                    promise.global().get_cx(),
                     Error::Type("Network error occurred".to_string()));
                 self.fetch_promise = Some(TrustedPromise::new(promise));
                 return;
diff --git a/components/script/script_runtime.rs b/components/script/script_runtime.rs
index 658ace4c46a..603e24a1468 100644
--- a/components/script/script_runtime.rs
+++ b/components/script/script_runtime.rs
@@ -8,11 +8,11 @@
 use dom::bindings::callback::ExceptionHandling;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::PromiseBinding::PromiseJobCallback;
-use dom::bindings::global::{global_root_from_object, GlobalRoot, GlobalRef};
-use dom::bindings::js::{RootCollection, RootCollectionPtr, trace_roots};
+use dom::bindings::js::{Root, RootCollection, RootCollectionPtr, trace_roots};
 use dom::bindings::refcounted::{LiveDOMReferences, trace_refcounted_objects};
 use dom::bindings::trace::trace_traceables;
 use dom::bindings::utils::DOM_CALLBACKS;
+use dom::globalscope::GlobalScope;
 use js::glue::CollectServoSizes;
 use js::jsapi::{DisableIncrementalGC, GCDescription, GCProgress, HandleObject};
 use js::jsapi::{JSContext, JS_GetRuntime, JSRuntime, JSTracer, SetDOMCallbacks, SetGCSliceCallback};
@@ -138,7 +138,7 @@ impl PromiseJobQueue {
 
     /// Add a new promise job callback to this queue. It will be invoked as part of the next
     /// microtask checkpoint.
-    pub fn enqueue(&self, job: EnqueuedPromiseCallback, global: GlobalRef) {
+    pub fn enqueue(&self, job: EnqueuedPromiseCallback, global: &GlobalScope) {
         self.promise_job_queue.borrow_mut().push(job);
         if !self.pending_promise_job_runnable.get() {
             self.pending_promise_job_runnable.set(true);
@@ -149,7 +149,7 @@ impl PromiseJobQueue {
     /// Perform a microtask checkpoint, by invoking all of the pending promise job callbacks in
     /// FIFO order (#4283).
     pub fn flush_promise_jobs<F>(&self, target_provider: F)
-        where F: Fn(PipelineId) -> Option<GlobalRoot>
+        where F: Fn(PipelineId) -> Option<Root<GlobalScope>>
     {
         self.pending_promise_job_runnable.set(false);
         {
@@ -161,7 +161,7 @@ impl PromiseJobQueue {
         // `flushing_queue` is a static snapshot during this checkpoint.
         for job in &*self.flushing_job_queue.borrow() {
             if let Some(target) = target_provider(job.pipeline) {
-                let _ = job.callback.Call_(&target.r(), ExceptionHandling::Report);
+                let _ = job.callback.Call_(&*target, ExceptionHandling::Report);
             }
         }
         self.flushing_job_queue.borrow_mut().clear();
@@ -177,9 +177,9 @@ unsafe extern "C" fn enqueue_job(_cx: *mut JSContext,
                                  _allocation_site: HandleObject,
                                  _data: *mut c_void) -> bool {
     let result = panic::catch_unwind(AssertUnwindSafe(|| {
-        let global = global_root_from_object(job.get());
-        let pipeline = global.r().pipeline_id();
-        global.r().enqueue_promise_job(EnqueuedPromiseCallback {
+        let global = GlobalScope::from_object(job.get());
+        let pipeline = global.pipeline_id();
+        global.enqueue_promise_job(EnqueuedPromiseCallback {
             callback: PromiseJobCallback::new(job.get()),
             pipeline: pipeline,
         });
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 61ecacda815..85f0cc2462e 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -27,7 +27,6 @@ use dom::bindings::codegen::Bindings::DocumentBinding::{DocumentMethods, Documen
 use dom::bindings::codegen::Bindings::LocationBinding::LocationMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::conversions::{ConversionResult, FromJSValConvertible, StringificationBehavior};
-use dom::bindings::global::{GlobalRef, GlobalRoot};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root, RootCollection};
 use dom::bindings::js::{RootCollectionPtr, RootedReference};
@@ -40,6 +39,7 @@ use dom::browsingcontext::BrowsingContext;
 use dom::document::{Document, DocumentProgressHandler, DocumentSource, FocusType, IsHTMLDocument};
 use dom::element::Element;
 use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::globalscope::GlobalScope;
 use dom::htmlanchorelement::HTMLAnchorElement;
 use dom::node::{Node, NodeDamage, window_from_node};
 use dom::serviceworker::TrustedServiceWorkerAddress;
@@ -169,7 +169,7 @@ impl InProgressLoad {
 
 /// Encapsulated state required to create cancellable runnables from non-script threads.
 pub struct RunnableWrapper {
-    pub cancelled: Arc<AtomicBool>,
+    pub cancelled: Option<Arc<AtomicBool>>,
 }
 
 impl RunnableWrapper {
@@ -183,7 +183,7 @@ impl RunnableWrapper {
 
 /// A runnable that can be discarded by toggling a shared flag.
 pub struct CancellableRunnable<T: Runnable + Send> {
-    cancelled: Arc<AtomicBool>,
+    cancelled: Option<Arc<AtomicBool>>,
     inner: Box<T>,
 }
 
@@ -191,7 +191,9 @@ impl<T: Runnable + Send> Runnable for CancellableRunnable<T> {
     fn name(&self) -> &'static str { self.inner.name() }
 
     fn is_cancelled(&self) -> bool {
-        self.cancelled.load(Ordering::SeqCst)
+        self.cancelled.as_ref()
+            .map(|cancelled| cancelled.load(Ordering::SeqCst))
+            .unwrap_or(false)
     }
 
     fn main_thread_handler(self: Box<CancellableRunnable<T>>, script_thread: &ScriptThread) {
@@ -649,7 +651,7 @@ impl ScriptThread {
                 let window = context.active_window();
                 let resize_event = window.steal_resize_event();
                 match resize_event {
-                    Some(size) => resizes.push((window.pipeline_id(), size)),
+                    Some(size) => resizes.push((window.upcast::<GlobalScope>().pipeline_id(), size)),
                     None => ()
                 }
             }
@@ -984,8 +986,7 @@ impl ScriptThread {
                     Some(browsing_context) => browsing_context.active_window(),
                     None => return warn!("Message sent to closed pipeline {}.", id),
                 };
-                let global_ref = GlobalRef::Window(window.r());
-                devtools::handle_evaluate_js(&global_ref, s, reply)
+                devtools::handle_evaluate_js(window.upcast(), s, reply)
             },
             DevtoolScriptControlMsg::GetRootNode(id, reply) =>
                 devtools::handle_get_root_node(&context, id, reply),
@@ -1004,8 +1005,7 @@ impl ScriptThread {
                     Some(browsing_context) => browsing_context.active_window(),
                     None => return warn!("Message sent to closed pipeline {}.", id),
                 };
-                let global_ref = GlobalRef::Window(window.r());
-                devtools::handle_wants_live_notifications(&global_ref, to_send)
+                devtools::handle_wants_live_notifications(window.upcast(), to_send)
             },
             DevtoolScriptControlMsg::SetTimelineMarkers(_pipeline_id, marker_types, reply) =>
                 devtools::handle_set_timeline_markers(&context, marker_types, reply),
@@ -1191,7 +1191,7 @@ impl ScriptThread {
 
         // https://html.spec.whatwg.org/multipage/#the-end step 7
         let handler = box DocumentProgressHandler::new(Trusted::new(doc));
-        self.dom_manipulation_task_source.queue(handler, GlobalRef::Window(doc.window())).unwrap();
+        self.dom_manipulation_task_source.queue(handler, doc.window().upcast()).unwrap();
 
         if let Some(fragment) = doc.url().fragment() {
             self.check_and_scroll_fragment(fragment, pipeline, doc);
@@ -1245,9 +1245,9 @@ impl ScriptThread {
             if let Some(ref inner_context) = root_context.find(id) {
                 let window = inner_context.active_window();
                 if visible {
-                    window.speed_up_timers();
+                    window.upcast::<GlobalScope>().speed_up_timers();
                 } else {
-                    window.slow_down_timers();
+                    window.upcast::<GlobalScope>().slow_down_timers();
                 }
                 return true;
             }
@@ -1292,7 +1292,7 @@ impl ScriptThread {
         if let Some(root_context) = self.browsing_context.get() {
             if let Some(ref inner_context) = root_context.find(id) {
                 let window = inner_context.active_window();
-                window.freeze();
+                window.upcast::<GlobalScope>().suspend();
                 return;
             }
         }
@@ -1449,10 +1449,9 @@ impl ScriptThread {
             None => return
         };
         if let Some(context) = self.root_browsing_context().find(pipeline_id) {
-            let window = context.active_window();
-            let global_ref = GlobalRef::Window(window.r());
             let script_url = maybe_registration.get_installed().get_script_url();
-            let scope_things = ServiceWorkerRegistration::create_scope_things(global_ref, script_url);
+            let scope_things = ServiceWorkerRegistration::create_scope_things(
+                context.active_window().upcast(), script_url);
             let _ = self.constellation_chan.send(ConstellationMsg::RegisterServiceWorker(scope_things, scope));
         } else {
             warn!("Registration failed for {}", scope);
@@ -1501,7 +1500,7 @@ impl ScriptThread {
         // If root is being exited, shut down all contexts
         let context = self.root_browsing_context();
         let window = context.active_window();
-        if window.pipeline_id() == id {
+        if window.upcast::<GlobalScope>().pipeline_id() == id {
             debug!("shutting down layout for root context {:?}", id);
             shut_down_layout(&context);
             let _ = self.constellation_chan.send(ConstellationMsg::PipelineExited(id));
@@ -1768,7 +1767,7 @@ impl ScriptThread {
             unsafe {
                 let _ac = JSAutoCompartment::new(self.get_cx(), window.reflector().get_jsobject().get());
                 rooted!(in(self.get_cx()) let mut jsval = UndefinedValue());
-                GlobalRef::Window(&window).evaluate_js_on_global_with_result(
+                window.upcast::<GlobalScope>().evaluate_js_on_global_with_result(
                     &script_source, jsval.handle_mut());
                 let strval = DOMString::from_jsval(self.get_cx(),
                                                    jsval.handle(),
@@ -1807,7 +1806,7 @@ impl ScriptThread {
         }
 
         if incomplete.is_frozen {
-            window.freeze();
+            window.upcast::<GlobalScope>().suspend();
         }
 
         if !incomplete.is_visible {
@@ -2153,7 +2152,7 @@ impl ScriptThread {
         };
 
         let window = context.active_window();
-        if window.live_devtools_updates() {
+        if window.upcast::<GlobalScope>().live_devtools_updates() {
             let css_error = CSSError {
                 filename: filename,
                 line: line,
@@ -2173,23 +2172,26 @@ impl ScriptThread {
         }
     }
 
-    pub fn enqueue_promise_job(job: EnqueuedPromiseCallback, global: GlobalRef) {
+    pub fn enqueue_promise_job(job: EnqueuedPromiseCallback, global: &GlobalScope) {
         SCRIPT_THREAD_ROOT.with(|root| {
             let script_thread = unsafe { &*root.get().unwrap() };
             script_thread.promise_job_queue.enqueue(job, global);
         });
     }
 
-    pub fn flush_promise_jobs(global: GlobalRef) {
+    pub fn flush_promise_jobs(global: &GlobalScope) {
         SCRIPT_THREAD_ROOT.with(|root| {
             let script_thread = unsafe { &*root.get().unwrap() };
-            let _ = script_thread.dom_manipulation_task_source.queue(box FlushPromiseJobs, global);
+            let _ = script_thread.dom_manipulation_task_source.queue(
+                box FlushPromiseJobs, global);
         })
     }
 
     fn do_flush_promise_jobs(&self) {
         self.promise_job_queue.flush_promise_jobs(|id| {
-            self.find_child_context(id).map(|context| GlobalRoot::Window(context.active_window()))
+            self.find_child_context(id).map(|context| {
+                Root::upcast(context.active_window())
+            })
         });
     }
 }
diff --git a/components/script/task_source/dom_manipulation.rs b/components/script/task_source/dom_manipulation.rs
index 4f5384ae2ed..c5b4e4b5f73 100644
--- a/components/script/task_source/dom_manipulation.rs
+++ b/components/script/task_source/dom_manipulation.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::refcounted::Trusted;
 use dom::event::{EventBubbles, EventCancelable, EventRunnable, SimpleEventRunnable};
 use dom::eventtarget::EventTarget;
@@ -41,7 +41,7 @@ impl DOMManipulationTaskSource {
             bubbles: bubbles,
             cancelable: cancelable,
         };
-        let _ = self.queue(runnable, GlobalRef::Window(window));
+        let _ = self.queue(runnable, window.upcast());
     }
 
     pub fn queue_simple_event(&self, target: &EventTarget, name: Atom, window: &Window) {
@@ -50,7 +50,7 @@ impl DOMManipulationTaskSource {
             target: target,
             name: name,
         };
-        let _ = self.queue(runnable, GlobalRef::Window(window));
+        let _ = self.queue(runnable, window.upcast());
     }
 }
 
diff --git a/components/script/task_source/mod.rs b/components/script/task_source/mod.rs
index cb607c57acb..6e2a9985fa0 100644
--- a/components/script/task_source/mod.rs
+++ b/components/script/task_source/mod.rs
@@ -8,7 +8,7 @@ pub mod history_traversal;
 pub mod networking;
 pub mod user_interaction;
 
-use dom::bindings::global::GlobalRef;
+use dom::globalscope::GlobalScope;
 use script_thread::{Runnable, RunnableWrapper};
 use std::result::Result;
 
@@ -18,7 +18,7 @@ pub trait TaskSource {
                              wrapper: &RunnableWrapper)
                              -> Result<(), ()>
                              where T: Runnable + Send + 'static;
-    fn queue<T: Runnable + Send + 'static>(&self, msg: Box<T>, global: GlobalRef) -> Result<(), ()> {
+    fn queue<T: Runnable + Send + 'static>(&self, msg: Box<T>, global: &GlobalScope) -> Result<(), ()> {
         self.queue_with_wrapper(msg, &global.get_runnable_wrapper())
     }
 }
diff --git a/components/script/task_source/user_interaction.rs b/components/script/task_source/user_interaction.rs
index cddafb80ee4..d3850e9f813 100644
--- a/components/script/task_source/user_interaction.rs
+++ b/components/script/task_source/user_interaction.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::global::GlobalRef;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::refcounted::Trusted;
 use dom::event::{EventBubbles, EventCancelable, EventRunnable};
 use dom::eventtarget::EventTarget;
@@ -41,7 +41,7 @@ impl UserInteractionTaskSource {
             bubbles: bubbles,
             cancelable: cancelable,
         };
-        let _ = self.queue(runnable, GlobalRef::Window(window));
+        let _ = self.queue(runnable, window.upcast());
     }
 }
 
diff --git a/components/script/timers.rs b/components/script/timers.rs
index 601755c6fc4..34ac02b6589 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -5,9 +5,9 @@
 use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
-use dom::bindings::global::GlobalRef;
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
 use dom::testbinding::TestBindingCallback;
 use dom::xmlhttprequest::XHRTimeoutCallback;
 use euclid::length::Length;
@@ -167,7 +167,7 @@ impl OneshotTimers {
         }
     }
 
-    pub fn fire_timer<T: Reflectable>(&self, id: TimerEventId, this: &T) {
+    pub fn fire_timer(&self, id: TimerEventId, global: &GlobalScope) {
         let expected_id = self.expected_event_id.get();
         if expected_id != id {
             debug!("ignoring timer fire event {:?} (expected {:?})", id, expected_id);
@@ -200,7 +200,7 @@ impl OneshotTimers {
 
         for timer in timers_to_run {
             let callback = timer.callback;
-            callback.invoke(this, &self.js_timers);
+            callback.invoke(global, &self.js_timers);
         }
 
         self.schedule_timer_call();
@@ -272,7 +272,7 @@ impl OneshotTimers {
     }
 
     pub fn set_timeout_or_interval(&self,
-                               global: GlobalRef,
+                               global: &GlobalScope,
                                callback: TimerCallback,
                                arguments: Vec<HandleValue>,
                                timeout: i32,
@@ -287,7 +287,7 @@ impl OneshotTimers {
                                                source)
     }
 
-    pub fn clear_timeout_or_interval(&self, global: GlobalRef, handle: i32) {
+    pub fn clear_timeout_or_interval(&self, global: &GlobalScope, handle: i32) {
         self.js_timers.clear_timeout_or_interval(global, handle)
     }
 }
@@ -364,7 +364,7 @@ impl JsTimers {
 
     // see https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
     pub fn set_timeout_or_interval(&self,
-                               global: GlobalRef,
+                               global: &GlobalScope,
                                callback: TimerCallback,
                                arguments: Vec<HandleValue>,
                                timeout: i32,
@@ -414,7 +414,7 @@ impl JsTimers {
         new_handle
     }
 
-    pub fn clear_timeout_or_interval(&self, global: GlobalRef, handle: i32) {
+    pub fn clear_timeout_or_interval(&self, global: &GlobalScope, handle: i32) {
         let mut active_timers = self.active_timers.borrow_mut();
 
         if let Some(entry) = active_timers.remove(&JsTimerHandle(handle)) {
@@ -441,7 +441,7 @@ impl JsTimers {
     }
 
     // see https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
-    fn initialize_and_schedule(&self, global: GlobalRef, mut task: JsTimerTask) {
+    fn initialize_and_schedule(&self, global: &GlobalScope, mut task: JsTimerTask) {
         let handle = task.handle;
         let mut active_timers = self.active_timers.borrow_mut();
 
@@ -490,10 +490,10 @@ impl JsTimerTask {
         match *&self.callback {
             InternalTimerCallback::StringTimerCallback(ref code_str) => {
                 let global = this.global();
-                let cx = global.r().get_cx();
+                let cx = global.get_cx();
                 rooted!(in(cx) let mut rval = UndefinedValue());
 
-                global.r().evaluate_js_on_global_with_result(
+                global.evaluate_js_on_global_with_result(
                     code_str, rval.handle_mut());
             },
             InternalTimerCallback::FunctionTimerCallback(ref function, ref arguments) => {
@@ -514,7 +514,7 @@ impl JsTimerTask {
         // reschedule repeating timers when they were not canceled as part of step 4.2.
         if self.is_interval == IsInterval::Interval &&
             timers.active_timers.borrow().contains_key(&self.handle) {
-            timers.initialize_and_schedule(this.global().r(), self);
+            timers.initialize_and_schedule(&this.global(), self);
         }
     }
 }
diff --git a/components/script/webdriver_handlers.rs b/components/script/webdriver_handlers.rs
index 03281464765..bcb0186d8e6 100644
--- a/components/script/webdriver_handlers.rs
+++ b/components/script/webdriver_handlers.rs
@@ -13,12 +13,12 @@ use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::NodeListBinding::NodeListMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::conversions::{ConversionResult, FromJSValConvertible, StringificationBehavior};
-use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::str::DOMString;
 use dom::browsingcontext::BrowsingContext;
 use dom::element::Element;
+use dom::globalscope::GlobalScope;
 use dom::htmlelement::HTMLElement;
 use dom::htmliframeelement::HTMLIFrameElement;
 use dom::htmlinputelement::HTMLInputElement;
@@ -92,7 +92,7 @@ pub fn handle_execute_script(context: &BrowsingContext,
     let result = unsafe {
         let cx = window.get_cx();
         rooted!(in(cx) let mut rval = UndefinedValue());
-        GlobalRef::Window(&window).evaluate_js_on_global_with_result(
+        window.upcast::<GlobalScope>().evaluate_js_on_global_with_result(
             &eval, rval.handle_mut());
         jsval_to_webdriver(cx, rval.handle())
     };
@@ -112,7 +112,7 @@ pub fn handle_execute_async_script(context: &BrowsingContext,
     let cx = window.get_cx();
     window.set_webdriver_script_chan(Some(reply));
     rooted!(in(cx) let mut rval = UndefinedValue());
-    GlobalRef::Window(&window).evaluate_js_on_global_with_result(
+    window.upcast::<GlobalScope>().evaluate_js_on_global_with_result(
         &eval, rval.handle_mut());
 }
 
@@ -142,7 +142,7 @@ pub fn handle_get_frame_id(context: &BrowsingContext,
         }
     };
 
-    let frame_id = window.map(|x| x.map(|x| x.pipeline_id()));
+    let frame_id = window.map(|x| x.map(|x| x.upcast::<GlobalScope>().pipeline_id()));
     reply.send(frame_id).unwrap()
 }
 
@@ -208,7 +208,7 @@ pub fn handle_get_cookies(context: &BrowsingContext,
     let document = context.active_document();
     let url = document.url();
     let (sender, receiver) = ipc::channel().unwrap();
-    let _ = document.window().resource_threads().send(
+    let _ = document.window().upcast::<GlobalScope>().resource_threads().send(
         GetCookiesDataForUrl(url.clone(), sender, NonHTTP)
         );
     let cookies = receiver.recv().unwrap();
@@ -223,7 +223,7 @@ pub fn handle_get_cookie(context: &BrowsingContext,
     let document = context.active_document();
     let url = document.url();
     let (sender, receiver) = ipc::channel().unwrap();
-    let _ = document.window().resource_threads().send(
+    let _ = document.window().upcast::<GlobalScope>().resource_threads().send(
         GetCookiesDataForUrl(url.clone(), sender, NonHTTP)
         );
     let cookies = receiver.recv().unwrap();
@@ -245,13 +245,13 @@ pub fn handle_add_cookie(context: &BrowsingContext,
     reply.send(match (document.is_cookie_averse(), cookie.domain.clone()) {
         (true, _) => Err(WebDriverCookieError::InvalidDomain),
         (false, Some(ref domain)) if url.host_str().map(|x| { x == &**domain }).unwrap_or(false) => {
-            let _ = document.window().resource_threads().send(
+            let _ = document.window().upcast::<GlobalScope>().resource_threads().send(
                 SetCookiesForUrlWithData(url.clone(), cookie, method)
                 );
             Ok(())
         },
         (false, None) => {
-            let _ = document.window().resource_threads().send(
+            let _ = document.window().upcast::<GlobalScope>().resource_threads().send(
                 SetCookiesForUrlWithData(url.clone(), cookie, method)
                 );
             Ok(())