Start reporting memory usage for Window and all nodes in all DOM trees for frame treese in script tasks.

33 files changed, 317 insertions, 107 deletions

diff --git a/components/msg/Cargo.toml b/components/msg/Cargo.toml
index edb799eee14..0575608d294 100644
--- a/components/msg/Cargo.toml
+++ b/components/msg/Cargo.toml
@@ -41,6 +41,9 @@ git = "https://github.com/pcwalton/ipc-channel"
 git = "https://github.com/ecoal95/rust-offscreen-rendering-context"
 features = ["texture_surface"]
 
+[dependencies.plugins]
+path = "../plugins"
+
 [dependencies]
 bitflags = "0.3"
 rustc-serialize = "0.3.4"
diff --git a/components/msg/constellation_msg.rs b/components/msg/constellation_msg.rs
index 97d673deecb..286d0f71a2b 100644
--- a/components/msg/constellation_msg.rs
+++ b/components/msg/constellation_msg.rs
@@ -48,7 +48,7 @@ pub struct Failure {
     pub parent_info: Option<(PipelineId, SubpageId)>,
 }
 
-#[derive(Copy, Clone, Deserialize, Serialize)]
+#[derive(Copy, Clone, Deserialize, Serialize, HeapSizeOf)]
 pub struct WindowSizeData {
     /// The size of the initial layout viewport, before parsing an
     /// http://www.w3.org/TR/css-device-adapt/#initial-viewport
@@ -386,13 +386,13 @@ pub enum NavigationDirection {
 #[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize)]
 pub struct FrameId(pub u32);
 
-#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize)]
+#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize, HeapSizeOf)]
 pub struct WorkerId(pub u32);
 
-#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize)]
+#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize, HeapSizeOf)]
 pub struct PipelineId(pub u32);
 
-#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize)]
+#[derive(Clone, PartialEq, Eq, Copy, Hash, Debug, Deserialize, Serialize, HeapSizeOf)]
 pub struct SubpageId(pub u32);
 
 // The type of pipeline exit. During complete shutdowns, pipelines do not have to
diff --git a/components/msg/lib.rs b/components/msg/lib.rs
index 4c2dd1f999b..7c03b73d591 100644
--- a/components/msg/lib.rs
+++ b/components/msg/lib.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #![feature(custom_derive, plugin)]
-#![plugin(serde_macros)]
+#![plugin(serde_macros, plugins)]
 
 extern crate azure;
 #[macro_use] extern crate bitflags;
diff --git a/components/script/document_loader.rs b/components/script/document_loader.rs
index 56ee98bdbbf..9046f5cbbcf 100644
--- a/components/script/document_loader.rs
+++ b/components/script/document_loader.rs
@@ -12,7 +12,7 @@ use net_traits::AsyncResponseTarget;
 use std::sync::Arc;
 use url::Url;
 
-#[derive(JSTraceable, PartialEq, Clone, Debug)]
+#[derive(JSTraceable, PartialEq, Clone, Debug, HeapSizeOf)]
 pub enum LoadType {
     Image(Url),
     Script(Url),
@@ -33,17 +33,19 @@ impl LoadType {
     }
 }
 
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 pub struct DocumentLoader {
     /// We use an `Arc<ResourceTask>` here in order to avoid file descriptor exhaustion when there
     /// are lots of iframes.
+    #[ignore_heap_size_of = "channels are hard"]
     pub resource_task: Arc<ResourceTask>,
     notifier_data: Option<NotifierData>,
     blocking_loads: Vec<LoadType>,
 }
 
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 pub struct NotifierData {
+    #[ignore_heap_size_of = "trait objects are hard"]
     pub script_chan: Box<ScriptChan + Send>,
     pub pipeline: PipelineId,
 }
diff --git a/components/script/dom/bindings/cell.rs b/components/script/dom/bindings/cell.rs
index 35b20d0a417..80bab8839bc 100644
--- a/components/script/dom/bindings/cell.rs
+++ b/components/script/dom/bindings/cell.rs
@@ -16,7 +16,7 @@ use std::cell::{BorrowState, RefCell, Ref, RefMut};
 ///
 /// This extends the API of `core::cell::RefCell` to allow unsafe access in
 /// certain situations, with dynamic checking in debug builds.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct DOMRefCell<T> {
     value: RefCell<T>,
 }
diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index a46c58ff7c7..9bfaa0c9cfd 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -3314,7 +3314,7 @@ class CGEnum(CGThing):
 
         decl = """\
 #[repr(usize)]
-#[derive(JSTraceable, PartialEq, Copy, Clone)]
+#[derive(JSTraceable, PartialEq, Copy, Clone, HeapSizeOf)]
 pub enum %s {
     %s
 }
diff --git a/components/script/dom/bindings/js.rs b/components/script/dom/bindings/js.rs
index fc929db1cac..0fde5678ab2 100644
--- a/components/script/dom/bindings/js.rs
+++ b/components/script/dom/bindings/js.rs
@@ -31,6 +31,7 @@ use js::jsapi::{JSObject, Heap, JSTracer};
 use js::jsval::JSVal;
 use layout_interface::TrustedNodeAddress;
 use script_task::STACK_ROOTS;
+use util::mem::HeapSizeOf;
 
 use core::nonzero::NonZero;
 use std::cell::{Cell, UnsafeCell};
@@ -44,6 +45,14 @@ pub struct JS<T> {
     ptr: NonZero<*const T>
 }
 
+// JS<T> is similar to Rc<T>, in that it's not always clear how to avoid double-counting.
+// For now, we choose not to follow any such pointers.
+impl<T> HeapSizeOf for JS<T> {
+    fn heap_size_of_children(&self) -> usize {
+        0
+    }
+}
+
 impl<T> JS<T> {
     /// Returns `LayoutJS<T>` containing the same pointer.
     pub unsafe fn to_layout(self) -> LayoutJS<T> {
@@ -226,7 +235,7 @@ impl<T: HeapGCValue+Copy> MutHeap<T> {
 /// place of traditional internal mutability to ensure that the proper GC
 /// barriers are enforced.
 #[must_root]
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 pub struct MutNullableHeap<T: HeapGCValue+Copy> {
     ptr: Cell<Option<T>>
 }
diff --git a/components/script/dom/bindings/utils.rs b/components/script/dom/bindings/utils.rs
index bacb6bc05ae..80db27bd894 100644
--- a/components/script/dom/bindings/utils.rs
+++ b/components/script/dom/bindings/utils.rs
@@ -16,6 +16,7 @@ use dom::bindings::js::Root;
 use dom::bindings::trace::trace_object;
 use dom::browsercontext;
 use dom::window;
+use util::mem::HeapSizeOf;
 use util::str::DOMString;
 
 use libc;
@@ -61,10 +62,18 @@ use js;
 use string_cache::{Atom, Namespace};
 
 /// Proxy handler for a WindowProxy.
+#[allow(raw_pointer_derive)]
 pub struct WindowProxyHandler(pub *const libc::c_void);
 
+impl HeapSizeOf for WindowProxyHandler {
+    fn heap_size_of_children(&self) -> usize {
+        //FIXME(#6907) this is a pointer to memory allocated by `new` in NewProxyHandler in rust-mozjs.
+        0
+    }
+}
+
 #[allow(raw_pointer_derive)]
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 /// Static data associated with a global object.
 pub struct GlobalStaticData {
     /// The WindowProxy proxy handler for this global.
@@ -416,8 +425,10 @@ pub fn reflect_dom_object<T: Reflectable>
 #[allow(raw_pointer_derive, unrooted_must_root)]
 #[must_root]
 #[servo_lang = "reflector"]
+#[derive(HeapSizeOf)]
 // If you're renaming or moving this field, update the path in plugins::reflector as well
 pub struct Reflector {
+    #[ignore_heap_size_of = "defined and measured in rust-mozjs"]
     object: UnsafeCell<*mut JSObject>,
 }
 
diff --git a/components/script/dom/browsercontext.rs b/components/script/dom/browsercontext.rs
index cc4dc346c3f..8fe518844ba 100644
--- a/components/script/dom/browsercontext.rs
+++ b/components/script/dom/browsercontext.rs
@@ -27,7 +27,7 @@ use js::{JSTrue, JSFalse};
 use std::ptr;
 use std::default::Default;
 
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
 #[allow(raw_pointer_derive)]
 #[must_root]
@@ -88,7 +88,7 @@ impl BrowsingContext {
 // without a reflector, so we don't mark this as #[dom_struct]
 #[must_root]
 #[privatize]
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 pub struct SessionHistoryEntry {
     document: JS<Document>,
     children: Vec<BrowsingContext>
diff --git a/components/script/dom/characterdata.rs b/components/script/dom/characterdata.rs
index 377a69b3d2d..f15b66c68f8 100644
--- a/components/script/dom/characterdata.rs
+++ b/components/script/dom/characterdata.rs
@@ -24,6 +24,7 @@ use std::cell::Ref;
 
 // https://dom.spec.whatwg.org/#characterdata
 #[dom_struct]
+#[derive(HeapSizeOf)]
 pub struct CharacterData {
     node: Node,
     data: DOMRefCell<DOMString>,
@@ -150,7 +151,7 @@ impl<'a> CharacterDataMethods for &'a CharacterData {
 }
 
 /// The different types of CharacterData.
-#[derive(JSTraceable, Copy, Clone, PartialEq, Debug)]
+#[derive(JSTraceable, Copy, Clone, PartialEq, Debug, HeapSizeOf)]
 pub enum CharacterDataTypeId {
     Comment,
     Text,
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index dd7dc90e0fe..5383ea6df33 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -110,6 +110,7 @@ pub enum IsHTMLDocument {
 
 // https://dom.spec.whatwg.org/#document
 #[dom_struct]
+#[derive(HeapSizeOf)]
 pub struct Document {
     node: Node,
     window: JS<Window>,
@@ -144,6 +145,7 @@ pub struct Document {
     animation_frame_ident: Cell<i32>,
     /// https://html.spec.whatwg.org/multipage/#list-of-animation-frame-callbacks
     /// List of animation frame callbacks
+    #[ignore_heap_size_of = "closures are hard"]
     animation_frame_list: RefCell<HashMap<i32, Box<Fn(f64)>>>,
     /// Tracks all outstanding loads related to this document.
     loader: DOMRefCell<DocumentLoader>,
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 046b9a57c5f..1b200ed4e61 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -120,7 +120,7 @@ impl PartialEq for Element {
     }
 }
 
-#[derive(JSTraceable, Copy, Clone, PartialEq, Debug)]
+#[derive(JSTraceable, Copy, Clone, PartialEq, Debug, HeapSizeOf)]
 pub enum ElementTypeId {
     HTMLElement(HTMLElementTypeId),
     Element,
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index dfeae4ff08f..79679ff14d2 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -20,6 +20,7 @@ use js::jsapi::{CompileFunction, JS_GetFunctionObject};
 use js::jsapi::{JSContext, RootedFunction, HandleObject};
 use js::jsapi::{JSAutoCompartment, JSAutoRequest};
 use js::rust::{AutoObjectVectorWrapper, CompileOptionsWrapper};
+use util::mem::HeapSizeOf;
 use util::str::DOMString;
 
 use fnv::FnvHasher;
@@ -36,13 +37,14 @@ use url::Url;
 
 use std::collections::HashMap;
 
-#[derive(JSTraceable, Copy, Clone, PartialEq)]
+#[derive(JSTraceable, Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum ListenerPhase {
     Capturing,
     Bubbling,
 }
 
 #[derive(JSTraceable, Copy, Clone)]
+#[derive(HeapSizeOf)]
 pub enum EventTargetTypeId {
     Node(NodeTypeId),
     WebSocket,
@@ -95,6 +97,13 @@ pub enum EventListenerType {
     Inline(Rc<EventListener>),
 }
 
+impl HeapSizeOf for EventListenerType {
+    fn heap_size_of_children(&self) -> usize {
+        // FIXME: Rc<T> isn't HeapSizeOf and we can't ignore it due to #6870 and #6871
+        0
+    }
+}
+
 impl EventListenerType {
     fn get_listener(&self) -> Rc<EventListener> {
         match *self {
@@ -104,7 +113,7 @@ impl EventListenerType {
     }
 }
 
-#[derive(JSTraceable, Clone, PartialEq)]
+#[derive(JSTraceable, Clone, PartialEq, HeapSizeOf)]
 #[privatize]
 pub struct EventListenerEntry {
     phase: ListenerPhase,
@@ -112,6 +121,7 @@ pub struct EventListenerEntry {
 }
 
 #[dom_struct]
+#[derive(HeapSizeOf)]
 pub struct EventTarget {
     reflector_: Reflector,
     type_id: EventTargetTypeId,
diff --git a/components/script/dom/htmlelement.rs b/components/script/dom/htmlelement.rs
index 376bec890cc..2a196073513 100644
--- a/components/script/dom/htmlelement.rs
+++ b/components/script/dom/htmlelement.rs
@@ -366,7 +366,7 @@ impl<'a> VirtualMethods for &'a HTMLElement {
     }
 }
 
-#[derive(JSTraceable, Copy, Clone, Debug)]
+#[derive(JSTraceable, Copy, Clone, Debug, HeapSizeOf)]
 pub enum HTMLElementTypeId {
     HTMLElement,
 
diff --git a/components/script/dom/htmlmediaelement.rs b/components/script/dom/htmlmediaelement.rs
index b0b3ae9c6e9..847132c6452 100644
--- a/components/script/dom/htmlmediaelement.rs
+++ b/components/script/dom/htmlmediaelement.rs
@@ -41,7 +41,7 @@ impl HTMLMediaElement {
     }
 }
 
-#[derive(JSTraceable, Copy, Clone, Debug)]
+#[derive(JSTraceable, Copy, Clone, Debug, HeapSizeOf)]
 pub enum HTMLMediaElementTypeId {
     HTMLAudioElement = 0,
     HTMLVideoElement = 1,
diff --git a/components/script/dom/htmltablecellelement.rs b/components/script/dom/htmltablecellelement.rs
index 66359deb22f..873cbb184e8 100644
--- a/components/script/dom/htmltablecellelement.rs
+++ b/components/script/dom/htmltablecellelement.rs
@@ -22,7 +22,7 @@ use std::cmp::max;
 
 const DEFAULT_COLSPAN: u32 = 1;
 
-#[derive(JSTraceable, Copy, Clone, Debug)]
+#[derive(JSTraceable, Copy, Clone, Debug, HeapSizeOf)]
 pub enum HTMLTableCellElementTypeId {
     HTMLTableDataCellElement = 0,
     HTMLTableHeaderCellElement = 1,
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 1f6a681e582..94a0a1e05c0 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -78,6 +78,7 @@ use string_cache::{Atom, Namespace, QualName};
 
 /// An HTML node.
 #[dom_struct]
+#[derive(HeapSizeOf)]
 pub struct Node {
     /// The JavaScript reflector for this node.
     eventtarget: EventTarget,
@@ -135,7 +136,7 @@ impl NodeDerived for EventTarget {
 
 bitflags! {
     #[doc = "Flags for node items."]
-    #[derive(JSTraceable)]
+    #[derive(JSTraceable, HeapSizeOf)]
     flags NodeFlags: u16 {
         #[doc = "Specifies whether this node is in a document."]
         const IS_IN_DOC = 0x01,
@@ -206,20 +207,25 @@ enum SuppressObserver {
 }
 
 /// Layout data that is shared between the script and layout tasks.
+#[derive(HeapSizeOf)]
 pub struct SharedLayoutData {
     /// The results of CSS styling for this node.
     pub style: Option<Arc<ComputedValues>>,
 }
 
 /// Encapsulates the abstract layout data.
+#[allow(raw_pointer_derive)]
+#[derive(HeapSizeOf)]
 pub struct LayoutData {
     _shared_data: SharedLayoutData,
+    #[ignore_heap_size_of = "TODO(#6910) Box value that should be counted but the type lives in layout"]
     _data: NonZero<*const ()>,
 }
 
 #[allow(unsafe_code)]
 unsafe impl Send for LayoutData {}
 
+#[derive(HeapSizeOf)]
 pub struct LayoutDataRef {
     data_cell: RefCell<Option<LayoutData>>,
 }
@@ -274,6 +280,7 @@ impl LayoutDataRef {
 
 /// The different types of nodes.
 #[derive(JSTraceable, Copy, Clone, PartialEq, Debug)]
+#[derive(HeapSizeOf)]
 pub enum NodeTypeId {
     CharacterData(CharacterDataTypeId),
     DocumentType,
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index af6f719f729..ba86c85b3ac 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -8,7 +8,7 @@ use dom::bindings::codegen::Bindings::EventHandlerBinding::{OnErrorEventHandlerN
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::codegen::Bindings::WindowBinding::{self, WindowMethods, FrameRequestCallback};
-use dom::bindings::codegen::InheritTypes::{NodeCast, ElementCast, EventTargetCast};
+use dom::bindings::codegen::InheritTypes::{NodeCast, ElementCast, EventTargetCast, WindowDerived};
 use dom::bindings::global::global_object_for_js_object;
 use dom::bindings::error::{report_pending_exception, Fallible};
 use dom::bindings::error::Error::InvalidCharacter;
@@ -81,7 +81,7 @@ use std::sync::mpsc::{channel, Receiver};
 use time;
 
 /// Current state of the window object
-#[derive(JSTraceable, Copy, Clone, Debug, PartialEq)]
+#[derive(JSTraceable, Copy, Clone, Debug, PartialEq, HeapSizeOf)]
 enum WindowState {
     Alive,
     Zombie,     // Pipeline is closed, but the window hasn't been GCed yet.
@@ -106,15 +106,21 @@ pub enum ReflowReason {
 }
 
 #[dom_struct]
+#[derive(HeapSizeOf)]
 pub struct Window {
     eventtarget: EventTarget,
+    #[ignore_heap_size_of = "trait objects are hard"]
     script_chan: Box<ScriptChan+Send>,
+    #[ignore_heap_size_of = "channels are hard"]
     control_chan: ScriptControlChan,
     console: MutNullableHeap<JS<Console>>,
     crypto: MutNullableHeap<JS<Crypto>>,
     navigator: MutNullableHeap<JS<Navigator>>,
+    #[ignore_heap_size_of = "channels are hard"]
     image_cache_task: ImageCacheTask,
+    #[ignore_heap_size_of = "channels are hard"]
     image_cache_chan: ImageCacheChan,
+    #[ignore_heap_size_of = "TODO(#6911) newtypes containing unmeasurable types are hard"]
     compositor: DOMRefCell<ScriptListener>,
     browsing_context: DOMRefCell<Option<BrowsingContext>>,
     page: Rc<Page>,
@@ -129,13 +135,17 @@ pub struct Window {
     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 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
+    #[ignore_heap_size_of = "TODO(#6909) need to measure HashSet"]
     devtools_markers: RefCell<HashSet<TimelineMarkerType>>,
+    #[ignore_heap_size_of = "channels are hard"]
     devtools_marker_sender: RefCell<Option<IpcSender<TimelineMarker>>>,
 
     /// A flag to indicate whether the developer tools have requested live updates of
@@ -160,27 +170,34 @@ pub struct Window {
     dom_static: GlobalStaticData,
 
     /// The JavaScript runtime.
+    #[ignore_heap_size_of = "Rc<T> is hard"]
     js_runtime: DOMRefCell<Option<Rc<Runtime>>>,
 
     /// A handle for communicating messages to the layout task.
+    #[ignore_heap_size_of = "channels are hard"]
     layout_chan: LayoutChan,
 
     /// A handle to perform RPC calls into the layout, quickly.
+    #[ignore_heap_size_of = "trait objects are hard"]
     layout_rpc: Box<LayoutRPC+'static>,
 
     /// The port that we will use to join layout. If this is `None`, then layout is not running.
+    #[ignore_heap_size_of = "channels are hard"]
     layout_join_port: DOMRefCell<Option<Receiver<()>>>,
 
     /// The current size of the window, in pixels.
     window_size: Cell<Option<WindowSizeData>>,
 
     /// Associated resource task for use by DOM objects like XMLHttpRequest
+    #[ignore_heap_size_of = "channels are hard"]
     resource_task: Arc<ResourceTask>,
 
     /// A handle for communicating messages to the storage task.
+    #[ignore_heap_size_of = "channels are hard"]
     storage_task: StorageTask,
 
     /// A handle for communicating messages to the constellation task.
+    #[ignore_heap_size_of = "channels are hard"]
     constellation_chan: ConstellationChan,
 
     /// Pending scroll to fragment event, if any
@@ -194,6 +211,7 @@ pub struct Window {
     pending_reflow_count: Cell<u32>,
 
     /// A channel for communicating results of async scripts back to the webdriver server
+    #[ignore_heap_size_of = "channels are hard"]
     webdriver_script_chan: RefCell<Option<IpcSender<WebDriverJSResult>>>,
 
     /// The current state of the window object
@@ -1182,3 +1200,9 @@ fn debug_reflow_events(goal: &ReflowGoal, query_type: &ReflowQueryType, reason:
 
     println!("{}", debug_msg);
 }
+
+impl WindowDerived for EventTarget {
+    fn is_window(&self) -> bool {
+        self.type_id() == &EventTargetTypeId::Window
+    }
+}
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index 91d140dc823..550834f7d09 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -37,7 +37,7 @@ use std::cell::Cell;
 use std::rc::Rc;
 use std::sync::mpsc::Receiver;
 
-#[derive(JSTraceable, Copy, Clone, PartialEq)]
+#[derive(JSTraceable, Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum WorkerGlobalScopeTypeId {
     DedicatedGlobalScope,
 }
diff --git a/components/script/dom/xmlhttprequesteventtarget.rs b/components/script/dom/xmlhttprequesteventtarget.rs
index 8c17d3c8b1a..6b50898ab27 100644
--- a/components/script/dom/xmlhttprequesteventtarget.rs
+++ b/components/script/dom/xmlhttprequesteventtarget.rs
@@ -8,7 +8,7 @@ use dom::bindings::codegen::InheritTypes::EventTargetCast;
 use dom::bindings::codegen::InheritTypes::XMLHttpRequestEventTargetDerived;
 use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 
-#[derive(JSTraceable, Copy, Clone, PartialEq)]
+#[derive(JSTraceable, Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum XMLHttpRequestEventTargetTypeId {
     XMLHttpRequest,
     XMLHttpRequestUpload,
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 47dadf0d956..8fc23dc78b4 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -84,6 +84,7 @@ pub mod dom;
 pub mod parse;
 
 pub mod layout_interface;
+mod mem;
 mod network_listener;
 pub mod page;
 pub mod script_task;
diff --git a/components/script/mem.rs b/components/script/mem.rs
new file mode 100644
index 00000000000..6dbd45e5b8a
--- /dev/null
+++ b/components/script/mem.rs
@@ -0,0 +1,36 @@
+/* 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/. */
+
+//! Routines for handling measuring the memory usage of arbitrary DOM nodes.
+
+use dom::bindings::codegen::InheritTypes::{DocumentCast, WindowCast, CharacterDataCast, NodeCast};
+use dom::eventtarget::{EventTarget, EventTargetTypeId};
+use dom::node::NodeTypeId;
+use libc;
+use util::mem::{HeapSizeOf, heap_size_of};
+
+// This is equivalent to measuring a Box<T>, except that DOM objects lose their
+// associated box in order to stash their pointers in a reserved slot of their
+// JS reflector. It is assumed that the caller passes a pointer to the most-derived
+// type that this pointer represents, or the actual heap usage of the pointee will
+// be under-reported.
+fn heap_size_of_self_and_children<T: HeapSizeOf>(obj: &T) -> usize {
+    heap_size_of(obj as *const T as *const libc::c_void) + obj.heap_size_of_children()
+}
+
+pub fn heap_size_of_eventtarget(target: &EventTarget) -> usize {
+    //TODO: add more specific matches for concrete element types as derive(HeapSizeOf) is
+    //      added to each one.
+    match target.type_id() {
+        &EventTargetTypeId::Window =>
+            heap_size_of_self_and_children(WindowCast::to_ref(target).unwrap()),
+        &EventTargetTypeId::Node(NodeTypeId::CharacterData(_)) =>
+            heap_size_of_self_and_children(CharacterDataCast::to_ref(target).unwrap()),
+        &EventTargetTypeId::Node(NodeTypeId::Document) =>
+            heap_size_of_self_and_children(DocumentCast::to_ref(target).unwrap()),
+        &EventTargetTypeId::Node(_) =>
+            heap_size_of_self_and_children(NodeCast::to_ref(target).unwrap()),
+        _ => 0,
+    }
+}
diff --git a/components/script/page.rs b/components/script/page.rs
index 1286a1427f1..f4b3fd6cd18 100644
--- a/components/script/page.rs
+++ b/components/script/page.rs
@@ -13,7 +13,7 @@ use std::cell::Cell;
 use std::rc::Rc;
 
 /// Encapsulates a handle to a frame in a frame tree.
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[allow(unrooted_must_root)] // FIXME(#6687) this is wrong
 pub struct Page {
     /// Pipeline id associated with this page.
@@ -127,7 +127,7 @@ impl Page {
 }
 
 /// Information for one frame in the browsing context.
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[must_root]
 pub struct Frame {
     /// The document for this frame.
diff --git a/components/script/script_task.rs b/components/script/script_task.rs
index 279ff364bda..b3ea5b16818 100644
--- a/components/script/script_task.rs
+++ b/components/script/script_task.rs
@@ -46,6 +46,7 @@ use dom::worker::TrustedWorkerAddress;
 use parse::html::{ParseContext, parse_html};
 use layout_interface::{self, NewLayoutTaskInfo, ScriptLayoutChan, LayoutChan, ReflowGoal};
 use layout_interface::{ReflowQueryType};
+use mem::heap_size_of_eventtarget;
 use network_listener::NetworkListener;
 use page::{Page, IterablePage, Frame};
 use timers::TimerId;
@@ -1104,11 +1105,28 @@ impl ScriptTask {
 
     fn collect_reports(&self, reports_chan: ReportsChan) {
         let mut urls = vec![];
+        let mut dom_tree_size = 0;
+        let mut reports = vec![];
         for it_page in self.root_page().iter() {
-            urls.push(it_page.document().url().serialize());
+            let current_url = it_page.document().url().serialize();
+            urls.push(current_url.clone());
+
+            for child in NodeCast::from_ref(&*it_page.document()).traverse_preorder() {
+                let target = EventTargetCast::from_ref(&*child);
+                dom_tree_size += heap_size_of_eventtarget(target);
+            }
+            let window = it_page.window();
+            let target = EventTargetCast::from_ref(&*window);
+            dom_tree_size += heap_size_of_eventtarget(target);
+
+            reports.push(Report {
+                path: path![format!("url({})", current_url), "dom-tree"],
+                kind: ReportKind::ExplicitJemallocHeapSize,
+                size: dom_tree_size,
+            })
         }
         let path_seg = format!("url({})", urls.join(", "));
-        let reports = ScriptTask::get_reports(self.get_cx(), path_seg);
+        reports.extend(ScriptTask::get_reports(self.get_cx(), path_seg));
         reports_chan.send(reports);
     }
 
diff --git a/components/script/timers.rs b/components/script/timers.rs
index 0a0a37e0a7a..ac7142914ad 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -13,6 +13,7 @@ use dom::window::ScriptHelpers;
 use script_task::{ScriptChan, ScriptMsg, TimerSource};
 use horribly_inefficient_timers;
 
+use util::mem::HeapSizeOf;
 use util::task::spawn_named;
 use util::str::DOMString;
 
@@ -29,14 +30,15 @@ use std::hash::{Hash, Hasher};
 use std::rc::Rc;
 use std::default::Default;
 
-#[derive(JSTraceable, PartialEq, Eq, Copy, Clone)]
+#[derive(JSTraceable, PartialEq, Eq, Copy, Clone, HeapSizeOf)]
 pub struct TimerId(i32);
 
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
 struct TimerHandle {
     handle: TimerId,
     data: TimerData,
+    #[ignore_heap_size_of = "channels are hard"]
     control_chan: Option<Sender<TimerControlMsg>>,
 }
 
@@ -46,6 +48,13 @@ pub enum TimerCallback {
     FunctionTimerCallback(Rc<Function>)
 }
 
+impl HeapSizeOf for TimerCallback {
+    fn heap_size_of_children(&self) -> usize {
+        // FIXME: Rc<T> isn't HeapSizeOf and we can't ignore it due to #6870 and #6871
+        0
+    }
+}
+
 impl Hash for TimerId {
     fn hash<H: Hasher>(&self, state: &mut H) {
         let TimerId(id) = *self;
@@ -65,7 +74,7 @@ impl TimerHandle {
     }
 }
 
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
 pub struct TimerManager {
     active_timers: DOMRefCell<HashMap<TimerId, TimerHandle>>,
@@ -82,7 +91,7 @@ impl Drop for TimerManager {
 }
 
 // Enum allowing more descriptive values for the is_interval field
-#[derive(JSTraceable, PartialEq, Copy, Clone)]
+#[derive(JSTraceable, PartialEq, Copy, Clone, HeapSizeOf)]
 pub enum IsInterval {
     Interval,
     NonInterval,
@@ -100,7 +109,7 @@ pub enum TimerControlMsg {
 // (ie. function value to invoke and all arguments to pass
 //      to the function when calling it)
 // TODO: Handle rooting during fire_timer when movable GC is turned on
-#[derive(JSTraceable)]
+#[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
 struct TimerData {
     is_interval: IsInterval,
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index 14f8284ed3e..9c4efbdb167 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -872,6 +872,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "offscreen_gl_context 0.1.0 (git+https://github.com/ecoal95/rust-offscreen-rendering-context)",
+ "plugins 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1502,7 +1503,10 @@ dependencies = [
  "bitflags 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "cssparser 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "html5ever 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
+ "js 0.1.0 (git+https://github.com/servo/rust-mozjs)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "lazy_static 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1514,6 +1518,7 @@ dependencies = [
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
diff --git a/components/style/properties.mako.rs b/components/style/properties.mako.rs
index 4010f46307f..36c2787dc76 100644
--- a/components/style/properties.mako.rs
+++ b/components/style/properties.mako.rs
@@ -486,7 +486,7 @@ pub mod longhands {
             use cssparser::ToCss;
             use std::fmt;
 
-            #[derive(PartialEq, Clone, Eq, Copy, Debug)]
+            #[derive(PartialEq, Clone, Eq, Copy, Debug, HeapSizeOf)]
             pub enum T {
                 Auto,
                 Number(i32),
@@ -604,7 +604,7 @@ pub mod longhands {
             use values::CSSFloat;
             use util::geometry::Au;
             use std::fmt;
-            #[derive(PartialEq, Copy, Clone)]
+            #[derive(PartialEq, Copy, Clone, HeapSizeOf)]
             pub enum T {
                 Normal,
                 Length(Au),
@@ -704,7 +704,7 @@ pub mod longhands {
             use util::geometry::Au;
             use std::fmt;
             #[allow(non_camel_case_types)]
-            #[derive(PartialEq, Copy, Clone)]
+            #[derive(PartialEq, Copy, Clone, HeapSizeOf)]
             pub enum T {
                 % for keyword in vertical_align_keywords:
                     ${to_rust_ident(keyword)},
@@ -812,7 +812,7 @@ pub mod longhands {
         }
 
         pub mod computed_value {
-            #[derive(Clone, Copy, PartialEq)]
+            #[derive(Clone, Copy, PartialEq, HeapSizeOf)]
             pub struct T(pub super::super::overflow_x::computed_value::T);
         }
 
@@ -865,7 +865,7 @@ pub mod longhands {
             use cssparser::{self, ToCss};
             use std::fmt;
 
-            #[derive(PartialEq, Eq, Clone)]
+            #[derive(PartialEq, Eq, Clone, HeapSizeOf)]
             pub enum ContentItem {
                 /// Literal string content.
                 String(String),
@@ -914,7 +914,7 @@ pub mod longhands {
             }
 
             #[allow(non_camel_case_types)]
-            #[derive(PartialEq, Eq, Clone)]
+            #[derive(PartialEq, Eq, Clone, HeapSizeOf)]
             pub enum T {
                 normal,
                 none,
@@ -1055,7 +1055,7 @@ pub mod longhands {
             use cssparser::{ToCss, Token};
             use std::fmt;
 
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Url>);
 
             impl ToCss for T {
@@ -1103,7 +1103,7 @@ pub mod longhands {
         pub use self::computed_value::T as SpecifiedValue;
 
         pub mod computed_value {
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<(String,String)>);
         }
 
@@ -1172,7 +1172,7 @@ pub mod longhands {
         pub use self::computed_value::T as SpecifiedValue;
 
         pub mod computed_value {
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<(String,i32)>);
         }
 
@@ -1247,7 +1247,7 @@ pub mod longhands {
 
         pub mod computed_value {
             use values::computed;
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<computed::Image>);
         }
 
@@ -1308,7 +1308,7 @@ pub mod longhands {
             pub mod computed_value {
                 use values::computed::LengthOrPercentage;
 
-                #[derive(PartialEq, Copy, Clone, Debug)]
+                #[derive(PartialEq, Copy, Clone, Debug, HeapSizeOf)]
                 pub struct T {
                     pub horizontal: LengthOrPercentage,
                     pub vertical: LengthOrPercentage,
@@ -1431,13 +1431,13 @@ pub mod longhands {
         pub mod computed_value {
             use values::computed::LengthOrPercentageOrAuto;
 
-            #[derive(PartialEq, Clone, Debug)]
+            #[derive(PartialEq, Clone, Debug, HeapSizeOf)]
             pub struct ExplicitSize {
                 pub width: LengthOrPercentageOrAuto,
                 pub height: LengthOrPercentageOrAuto,
             }
 
-            #[derive(PartialEq, Clone, Debug)]
+            #[derive(PartialEq, Clone, Debug, HeapSizeOf)]
             pub enum T {
                 Explicit(ExplicitSize),
                 Cover,
@@ -1613,7 +1613,7 @@ pub mod longhands {
             use string_cache::Atom;
             use std::fmt;
 
-            #[derive(PartialEq, Eq, Clone, Hash)]
+            #[derive(PartialEq, Eq, Clone, Hash, HeapSizeOf)]
             pub enum FontFamily {
                 FamilyName(Atom),
                 // Generic
@@ -1649,7 +1649,7 @@ pub mod longhands {
                     Ok(())
                 }
             }
-            #[derive(Clone, PartialEq, Eq, Hash)]
+            #[derive(Clone, PartialEq, Eq, Hash, HeapSizeOf)]
             pub struct T(pub Vec<FontFamily>);
         }
 
@@ -1741,7 +1741,7 @@ pub mod longhands {
         }
         pub mod computed_value {
             use std::fmt;
-            #[derive(PartialEq, Eq, Copy, Clone, Hash, Deserialize, Serialize)]
+            #[derive(PartialEq, Eq, Copy, Clone, Hash, Deserialize, Serialize, HeapSizeOf)]
             pub enum T {
                 % for weight in range(100, 901, 100):
                     Weight${weight} = ${weight},
@@ -1958,7 +1958,7 @@ pub mod longhands {
 
         pub mod computed_value {
             use util::geometry::Au;
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Au>);
         }
 
@@ -2020,7 +2020,7 @@ pub mod longhands {
 
         pub mod computed_value {
             use util::geometry::Au;
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Au>);
         }
 
@@ -2085,7 +2085,7 @@ pub mod longhands {
 
         impl ComputedValueAsSpecified for SpecifiedValue {}
 
-        #[derive(PartialEq, Eq, Copy, Clone, Debug)]
+        #[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
         pub struct SpecifiedValue {
             pub underline: bool,
             pub overline: bool,
@@ -2178,7 +2178,7 @@ pub mod longhands {
 
         impl ComputedValueAsSpecified for SpecifiedValue {}
 
-        #[derive(Clone, PartialEq, Copy, Debug)]
+        #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
         pub struct SpecifiedValue {
             pub underline: Option<RGBA>,
             pub overline: Option<RGBA>,
@@ -2286,7 +2286,7 @@ pub mod longhands {
         pub mod computed_value {
             use util::geometry::Au;
 
-            #[derive(Clone, Copy, Debug, PartialEq, RustcEncodable)]
+            #[derive(Clone, Copy, Debug, PartialEq, RustcEncodable, HeapSizeOf)]
             pub struct T {
                 pub horizontal: Au,
                 pub vertical: Au,
@@ -2398,7 +2398,7 @@ pub mod longhands {
             use std::fmt;
             use util::cursor::Cursor;
 
-            #[derive(Clone, PartialEq, Eq, Copy, Debug)]
+            #[derive(Clone, PartialEq, Eq, Copy, Debug, HeapSizeOf)]
             pub enum T {
                 AutoCursor,
                 SpecifiedCursor(Cursor),
@@ -2460,7 +2460,7 @@ pub mod longhands {
 
         pub mod computed_value {
             use util::geometry::Au;
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Au>);
         }
 
@@ -2521,7 +2521,7 @@ pub mod longhands {
         }
 
         pub mod computed_value {
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<u32>);
         }
 
@@ -2588,7 +2588,7 @@ pub mod longhands {
 
         pub mod computed_value {
             use util::geometry::Au;
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Au>);
         }
 
@@ -2734,10 +2734,10 @@ pub mod longhands {
             use values::computed;
             use std::fmt;
 
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<BoxShadow>);
 
-            #[derive(Clone, PartialEq, Copy)]
+            #[derive(Clone, PartialEq, Copy, HeapSizeOf)]
             pub struct BoxShadow {
                 pub offset_x: Au,
                 pub offset_y: Au,
@@ -2903,7 +2903,7 @@ pub mod longhands {
         pub mod computed_value {
             use util::geometry::Au;
 
-            #[derive(Clone, PartialEq, Eq, Copy, Debug)]
+            #[derive(Clone, PartialEq, Eq, Copy, Debug, HeapSizeOf)]
             pub struct ClipRect {
                 pub top: Au,
                 pub right: Option<Au>,
@@ -2911,7 +2911,7 @@ pub mod longhands {
                 pub left: Au,
             }
 
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<ClipRect>);
         }
 
@@ -3081,10 +3081,10 @@ pub mod longhands {
             use cssparser::Color;
             use util::geometry::Au;
 
-            #[derive(Clone, PartialEq, Debug)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
             pub struct T(pub Vec<TextShadow>);
 
-            #[derive(Clone, PartialEq, Debug)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
             pub struct TextShadow {
                 pub offset_x: Au,
                 pub offset_y: Au,
@@ -3484,7 +3484,7 @@ pub mod longhands {
             use values::CSSFloat;
             use values::computed;
 
-            #[derive(Clone, Copy, Debug, PartialEq)]
+            #[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf)]
             pub struct ComputedMatrix {
                 pub m11: CSSFloat, pub m12: CSSFloat, pub m13: CSSFloat, pub m14: CSSFloat,
                 pub m21: CSSFloat, pub m22: CSSFloat, pub m23: CSSFloat, pub m24: CSSFloat,
@@ -3503,7 +3503,7 @@ pub mod longhands {
                 }
             }
 
-            #[derive(Clone, Debug, PartialEq)]
+            #[derive(Clone, Debug, PartialEq, HeapSizeOf)]
             pub enum ComputedOperation {
                 Matrix(ComputedMatrix),
                 Skew(CSSFloat, CSSFloat),
@@ -3515,7 +3515,7 @@ pub mod longhands {
                 Perspective(computed::Length),
             }
 
-            #[derive(Clone, Debug, PartialEq)]
+            #[derive(Clone, Debug, PartialEq, HeapSizeOf)]
             pub struct T(pub Option<Vec<ComputedOperation>>);
         }
 
@@ -3934,7 +3934,7 @@ pub mod longhands {
         pub mod computed_value {
             use values::computed::{Length, LengthOrPercentage};
 
-            #[derive(Clone, Copy, Debug, PartialEq)]
+            #[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf)]
             pub struct T {
                 pub horizontal: LengthOrPercentage,
                 pub vertical: LengthOrPercentage,
@@ -4082,7 +4082,7 @@ pub mod longhands {
         pub mod computed_value {
             use values::computed::LengthOrPercentage;
 
-            #[derive(Clone, Copy, Debug, PartialEq)]
+            #[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf)]
             pub struct T {
                 pub horizontal: LengthOrPercentage,
                 pub vertical: LengthOrPercentage,
@@ -4275,7 +4275,7 @@ pub mod longhands {
 
             pub use values::computed::Time as SingleComputedValue;
 
-            #[derive(Clone, PartialEq)]
+            #[derive(Clone, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<SingleComputedValue>);
 
             impl ToComputedValue for T {
@@ -4382,7 +4382,7 @@ pub mod longhands {
 
             pub use self::TransitionTimingFunction as SingleComputedValue;
 
-            #[derive(Copy, Clone, Debug, PartialEq)]
+            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf)]
             pub enum TransitionTimingFunction {
                 CubicBezier(Point2D<f32>, Point2D<f32>),
                 Steps(u32, StartEnd),
@@ -4413,7 +4413,7 @@ pub mod longhands {
                 }
             }
 
-            #[derive(Copy, Clone, Debug, PartialEq)]
+            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf)]
             pub enum StartEnd {
                 Start,
                 End,
@@ -4428,7 +4428,7 @@ pub mod longhands {
                 }
             }
 
-            #[derive(Clone, Debug, PartialEq)]
+            #[derive(Clone, Debug, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<TransitionTimingFunction>);
 
             impl ToCss for T {
@@ -4535,7 +4535,7 @@ pub mod longhands {
 
             pub use self::TransitionProperty as SingleComputedValue;
 
-            #[derive(Copy, Clone, Debug, PartialEq)]
+            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf)]
             pub enum TransitionProperty {
                 All,
                 BackgroundColor,
@@ -4686,7 +4686,7 @@ pub mod longhands {
                 }
             }
 
-            #[derive(Clone, Debug, PartialEq)]
+            #[derive(Clone, Debug, PartialEq, HeapSizeOf)]
             pub struct T(pub Vec<SingleComputedValue>);
 
             impl ToCss for T {
@@ -5781,7 +5781,7 @@ pub mod style_structs {
     use super::longhands;
 
     % for style_struct in STYLE_STRUCTS:
-        #[derive(PartialEq, Clone)]
+        #[derive(PartialEq, Clone, HeapSizeOf)]
         pub struct ${style_struct.name} {
             % for longhand in style_struct.longhands:
                 pub ${longhand.ident}: longhands::${longhand.ident}::computed_value::T,
@@ -5793,7 +5793,7 @@ pub mod style_structs {
     % endfor
 }
 
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct ComputedValues {
     % for style_struct in STYLE_STRUCTS:
         ${style_struct.ident}: Arc<style_structs::${style_struct.name}>,
diff --git a/components/style/values.rs b/components/style/values.rs
index 03167b3fd36..da542f812fe 100644
--- a/components/style/values.rs
+++ b/components/style/values.rs
@@ -103,7 +103,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Debug)]
+    #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
     pub struct CSSColor {
         pub parsed: cssparser::Color,
         pub authored: Option<String>,
@@ -147,7 +147,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum FontRelativeLength {
         Em(CSSFloat),
         Ex(CSSFloat),
@@ -181,7 +181,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum ViewportPercentageLength {
         Vw(CSSFloat),
         Vh(CSSFloat),
@@ -222,7 +222,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub struct CharacterWidth(pub i32);
 
     impl CharacterWidth {
@@ -237,7 +237,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum Length {
         Absolute(Au),  // application units
         FontRelative(FontRelativeLength),
@@ -354,7 +354,7 @@ pub mod specified {
     }
 
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum LengthOrPercentage {
         Length(Length),
         Percentage(CSSFloat),  // [0 .. 100%] maps to [0.0 .. 1.0]
@@ -398,7 +398,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum LengthOrPercentageOrAuto {
         Length(Length),
         Percentage(CSSFloat),  // [0 .. 100%] maps to [0.0 .. 1.0]
@@ -442,7 +442,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum LengthOrPercentageOrNone {
         Length(Length),
         Percentage(CSSFloat),  // [0 .. 100%] maps to [0.0 .. 1.0]
@@ -486,7 +486,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum LengthOrNone {
         Length(Length),
         None,
@@ -617,7 +617,7 @@ pub mod specified {
     }
 
     /// Specified values for an image according to CSS-IMAGES.
-    #[derive(Clone, PartialEq, Debug)]
+    #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
     pub enum Image {
         Url(Url),
         LinearGradient(LinearGradient),
@@ -658,7 +658,7 @@ pub mod specified {
     }
 
     /// Specified values for a CSS linear gradient.
-    #[derive(Clone, PartialEq, Debug)]
+    #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
     pub struct LinearGradient {
         /// The angle or corner of the gradient.
         pub angle_or_corner: AngleOrCorner,
@@ -681,7 +681,7 @@ pub mod specified {
     }
 
     /// Specified values for an angle or a corner in a linear gradient.
-    #[derive(Clone, PartialEq, Copy, Debug)]
+    #[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
     pub enum AngleOrCorner {
         Angle(Angle),
         Corner(HorizontalDirection, VerticalDirection),
@@ -703,7 +703,7 @@ pub mod specified {
     }
 
     /// Specified values for one color stop in a linear gradient.
-    #[derive(Clone, PartialEq, Debug)]
+    #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
     pub struct ColorStop {
         /// The color of this stop.
         pub color: CSSColor,
@@ -810,7 +810,7 @@ pub mod specified {
     }
 
     /// A time in seconds according to CSS-VALUES § 6.2.
-    #[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
+    #[derive(Clone, Copy, Debug, PartialEq, PartialOrd, HeapSizeOf)]
     pub struct Time(pub CSSFloat);
 
     impl Time {
@@ -938,7 +938,7 @@ pub mod computed {
         }
     }
 
-    #[derive(PartialEq, Clone, Copy)]
+    #[derive(PartialEq, Clone, Copy, HeapSizeOf)]
     pub enum LengthOrPercentage {
         Length(Au),
         Percentage(CSSFloat),
@@ -984,7 +984,7 @@ pub mod computed {
         }
     }
 
-    #[derive(PartialEq, Clone, Copy)]
+    #[derive(PartialEq, Clone, Copy, HeapSizeOf)]
     pub enum LengthOrPercentageOrAuto {
         Length(Au),
         Percentage(CSSFloat),
@@ -1030,7 +1030,7 @@ pub mod computed {
         }
     }
 
-    #[derive(PartialEq, Clone, Copy)]
+    #[derive(PartialEq, Clone, Copy, HeapSizeOf)]
     pub enum LengthOrPercentageOrNone {
         Length(Au),
         Percentage(CSSFloat),
@@ -1076,7 +1076,7 @@ pub mod computed {
         }
     }
 
-    #[derive(PartialEq, Clone, Copy)]
+    #[derive(PartialEq, Clone, Copy, HeapSizeOf)]
     pub enum LengthOrNone {
         Length(Au),
         None,
@@ -1131,7 +1131,7 @@ pub mod computed {
 
 
     /// Computed values for an image according to CSS-IMAGES.
-    #[derive(Clone, PartialEq)]
+    #[derive(Clone, PartialEq, HeapSizeOf)]
     pub enum Image {
         Url(Url),
         LinearGradient(LinearGradient),
@@ -1147,7 +1147,7 @@ pub mod computed {
     }
 
     /// Computed values for a CSS linear gradient.
-    #[derive(Clone, PartialEq)]
+    #[derive(Clone, PartialEq, HeapSizeOf)]
     pub struct LinearGradient {
         /// The angle or corner of the gradient.
         pub angle_or_corner: AngleOrCorner,
@@ -1180,7 +1180,7 @@ pub mod computed {
     }
 
     /// Computed values for one color stop in a linear gradient.
-    #[derive(Clone, PartialEq, Copy)]
+    #[derive(Clone, PartialEq, Copy, HeapSizeOf)]
     pub struct ColorStop {
         /// The color of this stop.
         pub color: CSSColor,
diff --git a/components/util/Cargo.toml b/components/util/Cargo.toml
index 4d9027653f9..5b8e9f726f8 100644
--- a/components/util/Cargo.toml
+++ b/components/util/Cargo.toml
@@ -21,6 +21,12 @@ path = "../plugins"
 [dependencies.azure]
 git = "https://github.com/servo/rust-azure"
 
+[dependencies.js]
+git = "https://github.com/servo/rust-mozjs"
+
+[dependencies.layers]
+git = "https://github.com/servo/rust-layers"
+
 [dependencies.cssparser]
 version = "0.3"
 features = [ "serde-serialization" ]
@@ -35,6 +41,7 @@ features = [ "serde_serialization" ]
 [dependencies]
 log = "0.3"
 bitflags = "0.3"
+html5ever = { version = "0.2.1", features = ["unstable"] }
 libc = "0.1"
 rand = "0.3"
 rustc-serialize = "0.3"
@@ -44,4 +51,5 @@ num = "0.1.24"
 euclid = "0.1"
 serde = "0.4"
 serde_macros = "0.4"
+string_cache = "0.1"
 lazy_static = "0.1"
diff --git a/components/util/lib.rs b/components/util/lib.rs
index 8db4b17f5ec..df3f90f5dfb 100644
--- a/components/util/lib.rs
+++ b/components/util/lib.rs
@@ -31,7 +31,10 @@ extern crate alloc;
 #[macro_use] extern crate cssparser;
 extern crate euclid;
 extern crate getopts;
+extern crate html5ever;
 extern crate ipc_channel;
+extern crate js;
+extern crate layers;
 extern crate libc;
 extern crate num as num_lib;
 extern crate num_cpus;
@@ -39,6 +42,7 @@ extern crate rand;
 extern crate rustc_serialize;
 extern crate serde;
 extern crate smallvec;
+extern crate string_cache;
 extern crate url;
 
 use std::sync::Arc;
diff --git a/components/util/mem.rs b/components/util/mem.rs
index 51ec56c0f05..370840b7a16 100644
--- a/components/util/mem.rs
+++ b/components/util/mem.rs
@@ -5,17 +5,30 @@
 //! Data structure measurement.
 
 use libc::{c_void, size_t};
-use std::cell::RefCell;
-use std::collections::LinkedList;
-use std::mem::transmute;
+use std::cell::{Cell, RefCell};
+use std::collections::{HashMap, LinkedList, hash_state};
+use std::hash::Hash;
+use std::mem::{size_of, transmute};
 use std::sync::Arc;
+use std::rc::Rc;
 
 
 use azure::azure_hl::Color;
+use cssparser::Color as CSSParserColor;
+use cssparser::RGBA;
 use cursor::Cursor;
 use euclid::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D, Matrix4};
-use geometry::Au;
+use euclid::length::Length;
+use euclid::scale_factor::ScaleFactor;
+use geometry::{PagePx, ViewportPx, Au};
+use html5ever::tree_builder::QuirksMode;
+use layers::geometry::DevicePixel;
+use js::jsapi::Heap;
+use js::rust::GCMethods;
+use js::jsval::JSVal;
+use logical_geometry::WritingMode;
 use range::Range;
+use string_cache::atom::Atom;
 use url;
 
 extern {
@@ -129,6 +142,12 @@ impl HeapSizeOf for url::Host {
     }
 }
 
+impl<T: HeapSizeOf, U: HeapSizeOf> HeapSizeOf for (T, U) {
+    fn heap_size_of_children(&self) -> usize {
+        self.0.heap_size_of_children() + self.1.heap_size_of_children()
+    }
+}
+
 impl<T: HeapSizeOf> HeapSizeOf for Arc<T> {
     fn heap_size_of_children(&self) -> usize {
         (**self).heap_size_of_children()
@@ -141,6 +160,12 @@ impl<T: HeapSizeOf> HeapSizeOf for RefCell<T> {
     }
 }
 
+impl<T: HeapSizeOf + Copy> HeapSizeOf for Cell<T> {
+    fn heap_size_of_children(&self) -> usize {
+        self.get().heap_size_of_children()
+    }
+}
+
 impl<T: HeapSizeOf> HeapSizeOf for Vec<T> {
     fn heap_size_of_children(&self) -> usize {
         heap_size_of(self.as_ptr() as *const c_void) +
@@ -148,6 +173,25 @@ impl<T: HeapSizeOf> HeapSizeOf for Vec<T> {
     }
 }
 
+impl<T> HeapSizeOf for Vec<Rc<T>> {
+    fn heap_size_of_children(&self) -> usize {
+        // The fate of measuring Rc<T> is still undecided, but we still want to measure
+        // the space used for storing them.
+        heap_size_of(self.as_ptr() as *const c_void)
+    }
+}
+
+impl<K: HeapSizeOf, V: HeapSizeOf, S> HeapSizeOf for HashMap<K, V, S>
+    where K: Eq + Hash, S: hash_state::HashState {
+    fn heap_size_of_children(&self) -> usize {
+        //TODO(#6908) measure actual bucket memory usage instead of approximating
+        let size = self.capacity() * (size_of::<V>() + size_of::<K>());
+        self.iter().fold(size, |n, (key, value)| {
+            n + key.heap_size_of_children() + value.heap_size_of_children()
+        })
+    }
+}
+
 // FIXME(njn): We can't implement HeapSizeOf accurately for LinkedList because it requires access
 // to the private Node type. Eventually we'll want to add HeapSizeOf (or equivalent) to Rust
 // itself. In the meantime, we use the dirty hack of transmuting LinkedList into an identical type
@@ -242,7 +286,15 @@ known_heap_size!(0, u8, u16, u32, u64, usize);
 known_heap_size!(0, i8, i16, i32, i64, isize);
 known_heap_size!(0, bool, f32, f64);
 
-known_heap_size!(0, Rect<T>, Point2D<T>, Size2D<T>, Matrix2D<T>, SideOffsets2D<T>);
+known_heap_size!(0, Rect<T>, Point2D<T>, Size2D<T>, Matrix2D<T>, SideOffsets2D<T>, Range<T>);
+known_heap_size!(0, Length<T, U>, ScaleFactor<T, U, V>);
 
-known_heap_size!(0, Au, Color, Cursor, Matrix4);
-known_heap_size!(0, Range<T>);
+known_heap_size!(0, Au, WritingMode, CSSParserColor, Color, RGBA, Cursor, Matrix4, Atom);
+known_heap_size!(0, JSVal, PagePx, ViewportPx, DevicePixel, QuirksMode);
+
+// This is measured properly by the heap measurement implemented in SpiderMonkey.
+impl<T: Copy + GCMethods<T>> HeapSizeOf for Heap<T> {
+    fn heap_size_of_children(&self) -> usize {
+        0
+    }
+}
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 72efd080eda..67ac282bfec 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -869,6 +869,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "offscreen_gl_context 0.1.0 (git+https://github.com/ecoal95/rust-offscreen-rendering-context)",
+ "plugins 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1490,6 +1491,8 @@ dependencies = [
  "cssparser 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
+ "js 0.1.0 (git+https://github.com/servo/rust-mozjs)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "lazy_static 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1501,6 +1504,7 @@ dependencies = [
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
diff --git a/ports/gonk/Cargo.lock b/ports/gonk/Cargo.lock
index 0e3c601ee9d..1b45696a94e 100644
--- a/ports/gonk/Cargo.lock
+++ b/ports/gonk/Cargo.lock
@@ -789,6 +789,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "offscreen_gl_context 0.1.0 (git+https://github.com/ecoal95/rust-offscreen-rendering-context)",
+ "plugins 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1373,6 +1374,8 @@ dependencies = [
  "cssparser 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
+ "js 0.1.0 (git+https://github.com/servo/rust-mozjs)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "lazy_static 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1384,6 +1387,7 @@ dependencies = [
  "serde 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]