cc: Remove the unused compositor thread variable and interface.

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index 3c99a1640acadd7216a42382219fd1e316751cd5..a734f3e9c33cb2eeea97541b75538e7c07b60df9 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -97,10 +97,6 @@ class COMPOSITOR_EXPORT ContextFactory {
   // Gets the GPU memory buffer manager.
   virtual gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager() = 0;
 
-  // Gets the compositor message loop, or NULL if not using threaded
-  // compositing.
-  virtual base::MessageLoopProxy* GetCompositorMessageLoop() = 0;
-
   // Creates a Surface ID allocator with a new namespace.
   virtual scoped_ptr<cc::SurfaceIdAllocator> CreateSurfaceIdAllocator() = 0;
 
@@ -315,7 +311,6 @@ class COMPOSITOR_EXPORT Compositor
   scoped_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
   scoped_refptr<cc::Layer> root_web_layer_;
   scoped_ptr<cc::LayerTreeHost> host_;
-  scoped_refptr<base::MessageLoopProxy> compositor_thread_loop_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // The manager of vsync parameters for this compositor.