Auto merge of #6150 - servo:smupgrade3, r=mbrubeck

Upgrade to Spidermonkey 39

> Here it is.
> 
> ~~There's two major things that are unfinished here:~~
> - ~~Dealing with the unroot_must_root lint. I'm not sure about the value of this lint with the new rooting API.~~ Done.
> - ~~Updating the Cargo.locks to point to the new SM and SM binding.~~ Done.
> 
> I also included my fixes for the rust update, but these will disappear in a rebase. A rust update is necessary to support calling `Drop` on `Heap<T>` correctly when `Heap<T>` is inside a `Rc<T>`. Otherwise `&self` points to the wrong location.
> 
> Incremental GC is disabled here. I'm not sure how to deal with the incremental barriers so that's left for later.
> 
> Generational GC works. SM doesn't work without it.
> 
> The biggest change here is to the rooting API. `Root` was made movable, and `Temporary` and `JSRef` was removed. Movable `Root`s means there's no need for `Temporary`, and `JSRef`s aren't needed generally since it can be assumed that being able to obtain a reference to a dom object means it's already rooted. References have their lifetime bound to the Roots that provided them. DOM objects that haven't passed through `reflect_dom_object` don't need to be rooted, and DOM objects that have passed through `reflect_dom_object` can't be obtained without being rooted through `native_from_reflector_jsmanaged` or `JS::<T>::root()`.
> 
> Support for `Heap<T>` ended up messier than I expected. It's split into two commits, but only because it's a bit difficult to fold them together. Supporting `Heap<T>` properly requires that that `Heap::<T>::set()` be called on something that won't move. I removed the Copy and Clone trait from `Heap<T>` so `Cell` can't hold `Heap<T>` - only `UnsafeCell` can hold it.
> 
> `CallbackObject` is a bit tricky - I moved all callbacks into `Rc<T>` in order to make sure that the pointer inside to a `*mut JSObject` doesn't move. This is necessary for supporting `Heap<T>`.
> 
> `RootedCollectionSet` is very general purpose now. Anything with `JSTraceable` can be rooted by `RootedCollectionSet`/`RootedTraceable`. Right now, `RootedTraceable` is only used to hold down dom objects before they're fully attached to their reflector. I had to make a custom mechanism to dispatch the trace call - couldn't figure out how to get trait objects working for this case.
> 
> This has been tested with the following zeal settings:
> 
> GC after every allocation
> JS_GC_ZEAL=2,1
> 
> GC after every 100 allocations (important for catching use-after-free bugs)
> JS_GC_ZEAL=2,100
> 
> Verify pre barriers
> JS_GC_ZEAL=4,1
> 
> Verify post barriers
> JS_GC_ZEAL=11,1

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1 files changed, 16 insertions, 17 deletions

diff --git a/components/script/dom/htmlstyleelement.rs b/components/script/dom/htmlstyleelement.rs
index 8ab295a24af..66ee4f79836 100644
--- a/components/script/dom/htmlstyleelement.rs
+++ b/components/script/dom/htmlstyleelement.rs
@@ -6,10 +6,10 @@ use dom::attr::AttrHelpers;
 use dom::bindings::codegen::Bindings::HTMLStyleElementBinding;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLElementCast, HTMLStyleElementDerived, NodeCast};
-use dom::bindings::js::{JSRef, OptionalRootable, Rootable, Temporary, RootedReference};
+use dom::bindings::js::Root;
 use dom::document::Document;
 use dom::eventtarget::{EventTarget, EventTargetTypeId};
-use dom::element::{Element, ElementTypeId, AttributeHandlers};
+use dom::element::{ElementTypeId, AttributeHandlers};
 use dom::htmlelement::{HTMLElement, HTMLElementTypeId};
 use dom::node::{Node, NodeHelpers, NodeTypeId, window_from_node};
 use dom::virtualmethods::VirtualMethods;
@@ -36,7 +36,7 @@ impl HTMLStyleElementDerived for EventTarget {
 impl HTMLStyleElement {
     fn new_inherited(localName: DOMString,
                      prefix: Option<DOMString>,
-                     document: JSRef<Document>) -> HTMLStyleElement {
+                     document: &Document) -> HTMLStyleElement {
         HTMLStyleElement {
             htmlelement: HTMLElement::new_inherited(HTMLElementTypeId::HTMLStyleElement, localName, prefix, document)
         }
@@ -45,7 +45,7 @@ impl HTMLStyleElement {
     #[allow(unrooted_must_root)]
     pub fn new(localName: DOMString,
                prefix: Option<DOMString>,
-               document: JSRef<Document>) -> Temporary<HTMLStyleElement> {
+               document: &Document) -> Root<HTMLStyleElement> {
         let element = HTMLStyleElement::new_inherited(localName, prefix, document);
         Node::reflect_node(box element, document, HTMLStyleElementBinding::Wrap)
     }
@@ -55,21 +55,20 @@ pub trait StyleElementHelpers {
     fn parse_own_css(self);
 }
 
-impl<'a> StyleElementHelpers for JSRef<'a, HTMLStyleElement> {
+impl<'a> StyleElementHelpers for &'a HTMLStyleElement {
     fn parse_own_css(self) {
-        let node: JSRef<Node> = NodeCast::from_ref(self);
-        let element: JSRef<Element> = ElementCast::from_ref(self);
+        let node = NodeCast::from_ref(self);
+        let element = ElementCast::from_ref(self);
         assert!(node.is_in_doc());
 
-        let win = window_from_node(node).root();
+        let win = window_from_node(node);
         let win = win.r();
         let url = win.get_url();
 
-        let mq_attribute = element.get_attribute(&ns!(""), &atom!("media")).root();
-        let value = mq_attribute.r().map(|a| a.value());
-        let mq_str = match value {
-            Some(ref value) => &***value,
-            None => "",
+        let mq_attribute = element.get_attribute(&ns!(""), &atom!("media"));
+        let mq_str = match mq_attribute {
+            Some(a) => String::from_str(&**a.r().value()),
+            None => String::new(),
         };
         let mut css_parser = CssParser::new(&mq_str);
         let media = parse_media_query_list(&mut css_parser);
@@ -81,18 +80,18 @@ impl<'a> StyleElementHelpers for JSRef<'a, HTMLStyleElement> {
     }
 }
 
-impl<'a> VirtualMethods for JSRef<'a, HTMLStyleElement> {
+impl<'a> VirtualMethods for &'a HTMLStyleElement {
     fn super_type<'b>(&'b self) -> Option<&'b VirtualMethods> {
-        let htmlelement: &JSRef<HTMLElement> = HTMLElementCast::from_borrowed_ref(self);
+        let htmlelement: &&HTMLElement = HTMLElementCast::from_borrowed_ref(self);
         Some(htmlelement as &VirtualMethods)
     }
 
-    fn child_inserted(&self, child: JSRef<Node>) {
+    fn child_inserted(&self, child: &Node) {
         if let Some(ref s) = self.super_type() {
             s.child_inserted(child);
         }
 
-        let node: JSRef<Node> = NodeCast::from_ref(*self);
+        let node = NodeCast::from_ref(*self);
         if node.is_in_doc() {
             self.parse_own_css();
         }