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, 24 insertions, 25 deletions

diff --git a/components/script/dom/htmltableelement.rs b/components/script/dom/htmltableelement.rs
index 0f254f07ad6..2ff2d69a0b5 100644
--- a/components/script/dom/htmltableelement.rs
+++ b/components/script/dom/htmltableelement.rs
@@ -8,7 +8,7 @@ use dom::bindings::codegen::Bindings::HTMLTableElementBinding;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::InheritTypes::{HTMLElementCast, HTMLTableCaptionElementCast};
 use dom::bindings::codegen::InheritTypes::{HTMLTableElementDerived, NodeCast};
-use dom::bindings::js::{JSRef, Rootable, Temporary, OptionalRootable, RootedReference};
+use dom::bindings::js::Root;
 use dom::document::Document;
 use dom::eventtarget::{EventTarget, EventTargetTypeId};
 use dom::element::ElementTypeId;
@@ -42,7 +42,7 @@ impl HTMLTableElementDerived for EventTarget {
 }
 
 impl HTMLTableElement {
-    fn new_inherited(localName: DOMString, prefix: Option<DOMString>, document: JSRef<Document>)
+    fn new_inherited(localName: DOMString, prefix: Option<DOMString>, document: &Document)
                      -> HTMLTableElement {
         HTMLTableElement {
             htmlelement: HTMLElement::new_inherited(HTMLElementTypeId::HTMLTableElement,
@@ -57,30 +57,29 @@ impl HTMLTableElement {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(localName: DOMString, prefix: Option<DOMString>, document: JSRef<Document>)
-               -> Temporary<HTMLTableElement> {
+    pub fn new(localName: DOMString, prefix: Option<DOMString>, document: &Document)
+               -> Root<HTMLTableElement> {
         let element = HTMLTableElement::new_inherited(localName, prefix, document);
         Node::reflect_node(box element, document, HTMLTableElementBinding::Wrap)
     }
 }
 
-impl<'a> HTMLTableElementMethods for JSRef<'a, HTMLTableElement> {
+impl<'a> HTMLTableElementMethods for &'a HTMLTableElement {
     //  https://www.whatwg.org/html/#dom-table-caption
-    fn GetCaption(self) -> Option<Temporary<HTMLTableCaptionElement>> {
-        let node: JSRef<Node> = NodeCast::from_ref(self);
+    fn GetCaption(self) -> Option<Root<HTMLTableCaptionElement>> {
+        let node = NodeCast::from_ref(self);
         node.children()
-            .map(|c| c.root())
             .filter_map(|c| {
-                HTMLTableCaptionElementCast::to_ref(c.r()).map(Temporary::from_rooted)
+                HTMLTableCaptionElementCast::to_ref(c.r()).map(Root::from_ref)
             })
             .next()
     }
 
     // https://www.whatwg.org/html/#dom-table-caption
-    fn SetCaption(self, new_caption: Option<JSRef<HTMLTableCaptionElement>>) {
-        let node: JSRef<Node> = NodeCast::from_ref(self);
+    fn SetCaption(self, new_caption: Option<&HTMLTableCaptionElement>) {
+        let node = NodeCast::from_ref(self);
 
-        if let Some(ref caption) = self.GetCaption().root() {
+        if let Some(ref caption) = self.GetCaption() {
             assert!(node.RemoveChild(NodeCast::from_ref(caption.r())).is_ok());
         }
 
@@ -91,37 +90,37 @@ impl<'a> HTMLTableElementMethods for JSRef<'a, HTMLTableElement> {
 }
 
 pub trait HTMLTableElementHelpers {
-    fn get_background_color(&self) -> Option<RGBA>;
-    fn get_border(&self) -> Option<u32>;
-    fn get_cellspacing(&self) -> Option<u32>;
-    fn get_width(&self) -> LengthOrPercentageOrAuto;
+    fn get_background_color(self) -> Option<RGBA>;
+    fn get_border(self) -> Option<u32>;
+    fn get_cellspacing(self) -> Option<u32>;
+    fn get_width(self) -> LengthOrPercentageOrAuto;
 }
 
-impl HTMLTableElementHelpers for HTMLTableElement {
-    fn get_background_color(&self) -> Option<RGBA> {
+impl<'a> HTMLTableElementHelpers for &'a HTMLTableElement {
+    fn get_background_color(self) -> Option<RGBA> {
         self.background_color.get()
     }
 
-    fn get_border(&self) -> Option<u32> {
+    fn get_border(self) -> Option<u32> {
         self.border.get()
     }
 
-    fn get_cellspacing(&self) -> Option<u32> {
+    fn get_cellspacing(self) -> Option<u32> {
         self.cellspacing.get()
     }
 
-    fn get_width(&self) -> LengthOrPercentageOrAuto {
+    fn get_width(self) -> LengthOrPercentageOrAuto {
         self.width.get()
     }
 }
 
-impl<'a> VirtualMethods for JSRef<'a, HTMLTableElement> {
+impl<'a> VirtualMethods for &'a HTMLTableElement {
     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 after_set_attr(&self, attr: JSRef<Attr>) {
+    fn after_set_attr(&self, attr: &Attr) {
         if let Some(ref s) = self.super_type() {
             s.after_set_attr(attr);
         }
@@ -143,7 +142,7 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLTableElement> {
         }
     }
 
-    fn before_remove_attr(&self, attr: JSRef<Attr>) {
+    fn before_remove_attr(&self, attr: &Attr) {
         if let Some(ref s) = self.super_type() {
             s.before_remove_attr(attr);
         }