compositing: Move messages that go over the ScriptListener to go over

an IPC channel instead.

Because this used a boxed trait object to invoke messages across a
process boundary, and boxed trait objects are not supported across IPC,
we spawn a helper thread inside the compositor to perform the marshaling
for us.

components/script/dom/bindings/trace.rs

@@ -328,7 +328,7 @@ impl<A,B> JSTraceable for fn(A) -> B {
     }
 }
 
-impl JSTraceable for Box<ScriptListener+'static> {
+impl JSTraceable for ScriptListener {
     #[inline]
     fn trace(&self, _: *mut JSTracer) {
         // Do nothing

components/script/dom/document.rs

@@ -251,8 +251,11 @@ pub trait DocumentHelpers<'a> {
     fn title_changed(self);
     fn send_title_to_compositor(self);
     fn dirty_all_nodes(self);
-    fn dispatch_key_event(self, key: Key, state: KeyState,
-        modifiers: KeyModifiers, compositor: &mut Box<ScriptListener+'static>);
+    fn dispatch_key_event(self,
+                          key: Key,
+                          state: KeyState,
+                          modifiers: KeyModifiers,
+                          compositor: &mut ScriptListener);
     fn node_from_nodes_and_strings(self, nodes: Vec<NodeOrString>)
                                    -> Fallible<Root<Node>>;
     fn get_body_attribute(self, local_name: &Atom) -> DOMString;
@@ -763,10 +766,11 @@ impl<'a> DocumentHelpers<'a> for &'a Document {
     }
 
     /// The entry point for all key processing for web content
-    fn dispatch_key_event(self, key: Key,
+    fn dispatch_key_event(self,
+                          key: Key,
                           state: KeyState,
                           modifiers: KeyModifiers,
-                          compositor: &mut Box<ScriptListener+'static>) {
+                          compositor: &mut ScriptListener) {
         let window = self.window.root();
         let focused = self.get_focused_element();
         let body = self.GetBody();

components/script/dom/window.rs

@@ -105,7 +105,7 @@ pub struct Window {
     navigator: MutNullableHeap<JS<Navigator>>,
     image_cache_task: ImageCacheTask,
     image_cache_chan: ImageCacheChan,
-    compositor: DOMRefCell<Box<ScriptListener+'static>>,
+    compositor: DOMRefCell<ScriptListener>,
     browser_context: DOMRefCell<Option<BrowserContext>>,
     page: Rc<Page>,
     performance: MutNullableHeap<JS<Performance>>,
@@ -241,7 +241,7 @@ impl Window {
         &self.image_cache_task
     }
 
-    pub fn compositor<'a>(&'a self) -> RefMut<'a, Box<ScriptListener+'static>> {
+    pub fn compositor<'a>(&'a self) -> RefMut<'a, ScriptListener> {
         self.compositor.borrow_mut()
     }
 
@@ -964,7 +964,7 @@ impl Window {
                script_chan: Box<ScriptChan+Send>,
                image_cache_chan: ImageCacheChan,
                control_chan: ScriptControlChan,
-               compositor: Box<ScriptListener+'static>,
+               compositor: ScriptListener,
                image_cache_task: ImageCacheTask,
                resource_task: ResourceTask,
                storage_task: StorageTask,

components/script/script_task.rs

@@ -297,8 +297,9 @@ pub struct ScriptTask {
 
     /// For communicating load url messages to the constellation
     constellation_chan: ConstellationChan,
+
     /// A handle to the compositor for communicating ready state messages.
-    compositor: DOMRefCell<Box<ScriptListener+'static>>,
+    compositor: DOMRefCell<ScriptListener>,
 
     /// The port on which we receive messages from the image cache
     image_cache_port: Receiver<ImageCacheResult>,
@@ -374,29 +375,28 @@ impl ScriptTaskFactory for ScriptTask {
         box pair.sender() as Box<Any+Send>
     }
 
-    fn create<C>(_phantom: Option<&mut ScriptTask>,
-                 id: PipelineId,
-                 parent_info: Option<(PipelineId, SubpageId)>,
-                 compositor: C,
-                 layout_chan: &OpaqueScriptLayoutChannel,
-                 control_chan: ScriptControlChan,
-                 control_port: Receiver<ConstellationControlMsg>,
-                 constellation_chan: ConstellationChan,
-                 failure_msg: Failure,
-                 resource_task: ResourceTask,
-                 storage_task: StorageTask,
-                 image_cache_task: ImageCacheTask,
-                 devtools_chan: Option<DevtoolsControlChan>,
-                 window_size: Option<WindowSizeData>,
-                 load_data: LoadData)
-                 where C: ScriptListener + Send + 'static {
+    fn create(_phantom: Option<&mut ScriptTask>,
+              id: PipelineId,
+              parent_info: Option<(PipelineId, SubpageId)>,
+              compositor: ScriptListener,
+              layout_chan: &OpaqueScriptLayoutChannel,
+              control_chan: ScriptControlChan,
+              control_port: Receiver<ConstellationControlMsg>,
+              constellation_chan: ConstellationChan,
+              failure_msg: Failure,
+              resource_task: ResourceTask,
+              storage_task: StorageTask,
+              image_cache_task: ImageCacheTask,
+              devtools_chan: Option<DevtoolsControlChan>,
+              window_size: Option<WindowSizeData>,
+              load_data: LoadData) {
         let ConstellationChan(const_chan) = constellation_chan.clone();
         let (script_chan, script_port) = channel();
         let layout_chan = LayoutChan(layout_chan.sender());
         spawn_named_with_send_on_failure(format!("ScriptTask {:?}", id), task_state::SCRIPT, move || {
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);
-            let script_task = ScriptTask::new(box compositor as Box<ScriptListener>,
+            let script_task = ScriptTask::new(compositor,
                                               script_port,
                                               NonWorkerScriptChan(script_chan),
                                               control_chan,
@@ -464,7 +464,7 @@ impl ScriptTask {
     }
 
     /// Creates a new script task.
-    pub fn new(compositor: Box<ScriptListener+'static>,
+    pub fn new(compositor: ScriptListener,
                port: Receiver<ScriptMsg>,
                chan: NonWorkerScriptChan,
                control_chan: ScriptControlChan,