Auto merge of #17068 - gterzian:remove_compositorproxy, r=asajeffrey

Separate waking the event loop, from communicating with Compositor

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@paulrouget first step of #15934, Glutin only for now, please take a look...

If this makes sense, I will also update the code for ports other than Glutin...

One question: one do I add the `warn!` macro to `servolib`? Also perhaps we would also want to add `box`, since I had to switch to using `Box::new`...

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components/compositing/compositor.rs

@@ -103,7 +103,7 @@ pub struct IOCompositor<Window: WindowMethods> {
     window: Rc<Window>,
 
     /// The port on which we receive messages.
-    port: Box<CompositorReceiver>,
+    port: CompositorReceiver,
 
     /// The root pipeline.
     root_pipeline: Option<CompositionPipeline>,
@@ -133,7 +133,7 @@ pub struct IOCompositor<Window: WindowMethods> {
     /// The device pixel ratio for this window.
     scale_factor: ScaleFactor<f32, DeviceIndependentPixel, DevicePixel>,
 
-    channel_to_self: Box<CompositorProxy + Send>,
+    channel_to_self: CompositorProxy,
 
     /// A handle to the delayed composition timer.
     delayed_composition_timer: DelayedCompositionTimerProxy,
@@ -312,11 +312,11 @@ fn initialize_png(gl: &gl::Gl, width: usize, height: usize) -> RenderTargetInfo
 }
 
 struct RenderNotifier {
-    compositor_proxy: Box<CompositorProxy>,
+    compositor_proxy: CompositorProxy,
 }
 
 impl RenderNotifier {
-    fn new(compositor_proxy: Box<CompositorProxy>,
+    fn new(compositor_proxy: CompositorProxy,
            _: Sender<ConstellationMsg>) -> RenderNotifier {
         RenderNotifier {
             compositor_proxy: compositor_proxy,
@@ -336,7 +336,7 @@ impl webrender_traits::RenderNotifier for RenderNotifier {
 
 // Used to dispatch functions from webrender to the main thread's event loop.
 struct CompositorThreadDispatcher {
-    compositor_proxy: Box<CompositorProxy>
+    compositor_proxy: CompositorProxy
 }
 
 impl webrender_traits::RenderDispatcher for CompositorThreadDispatcher {