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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- [ ] These changes fix #__ (github issue number if applicable).

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components/servo/lib.rs

@@ -68,8 +68,8 @@ fn webdriver(_port: u16, _constellation: Sender<ConstellationMsg>) { }
 
 use bluetooth::BluetoothThreadFactory;
 use bluetooth_traits::BluetoothRequest;
-use compositing::{CompositorProxy, IOCompositor};
-use compositing::compositor_thread::InitialCompositorState;
+use compositing::IOCompositor;
+use compositing::compositor_thread::{self, CompositorProxy, CompositorReceiver, InitialCompositorState};
 use compositing::windowing::WindowEvent;
 use compositing::windowing::WindowMethods;
 use constellation::{Constellation, InitialConstellationState, UnprivilegedPipelineContent};
@@ -97,7 +97,7 @@ use std::borrow::Cow;
 use std::cmp::max;
 use std::path::PathBuf;
 use std::rc::Rc;
-use std::sync::mpsc::Sender;
+use std::sync::mpsc::{Sender, channel};
 use webrender::renderer::RendererKind;
 use webvr::{WebVRThread, WebVRCompositorHandler};
 
@@ -134,7 +134,7 @@ impl<Window> Browser<Window> where Window: WindowMethods + 'static {
         // messages to client may need to pump a platform-specific event loop
         // to deliver the message.
         let (compositor_proxy, compositor_receiver) =
-            window.create_compositor_channel();
+            create_compositor_channel(window.create_event_loop_waker());
         let supports_clipboard = window.supports_clipboard();
         let time_profiler_chan = profile_time::Profiler::create(&opts.time_profiling,
                                                                 opts.time_profiler_trace_path.clone());
@@ -273,10 +273,22 @@ impl<Window> Browser<Window> where Window: WindowMethods + 'static {
     }
 }
 
+fn create_compositor_channel(event_loop_waker: Box<compositor_thread::EventLoopWaker>)
+    -> (CompositorProxy, CompositorReceiver) {
+    let (sender, receiver) = channel();
+    (CompositorProxy {
+         sender: sender,
+         event_loop_waker: event_loop_waker,
+        },
+     CompositorReceiver {
+         receiver: receiver
+     })
+}
+
 fn create_constellation(user_agent: Cow<'static, str>,
                         config_dir: Option<PathBuf>,
                         url: Option<ServoUrl>,
-                        compositor_proxy: Box<CompositorProxy + Send>,
+                        compositor_proxy: CompositorProxy,
                         time_profiler_chan: time::ProfilerChan,
                         mem_profiler_chan: mem::ProfilerChan,
                         debugger_chan: Option<debugger::Sender>,