WIP: Propagate SurfaceID up window tree hierarchy

services/ui/ws/frame_generator.h

Index: services/ui/ws/frame_generator.h
diff --git a/services/ui/ws/frame_generator.h b/services/ui/ws/frame_generator.h
index 00b296a9eaf960b1f3e5ffd115efceae97d957da..d28cfa9c2a1b78ca35c5b2313aced37a03eb14f7 100644
--- a/services/ui/ws/frame_generator.h
+++ b/services/ui/ws/frame_generator.h
@@ -24,8 +24,10 @@ class GpuChannelHost;
 
 namespace ui {
 
+namespace surfaces {
+class CompositorFrameSink;
 class DisplayCompositor;
-class SurfacesState;
+}
 
 namespace ws {
 
@@ -37,11 +39,11 @@ class FrameGeneratorDelegate;
 class ServerWindow;
 
 // Responsible for redrawing the display in response to the redraw requests by
-// submitting CompositorFrames to the owned DisplayCompositor.
+// submitting CompositorFrames to the owned CompositorFrameSink.
 class FrameGenerator {
  public:
   FrameGenerator(FrameGeneratorDelegate* delegate,
-                 scoped_refptr<SurfacesState> surfaces_state);
+                 scoped_refptr<surfaces::DisplayCompositor> display_compositor);
   virtual ~FrameGenerator();
 
   void OnGpuChannelEstablished(scoped_refptr<gpu::GpuChannelHost> gpu_channel);
@@ -64,7 +66,7 @@ class FrameGenerator {
   // http://crbug.com/533042
   void Draw();
 
-  // This is called after the DisplayCompositor has completed generating a new
+  // This is called after the CompositorFrameSink has completed generating a new
   // frame for the display. TODO(fsamuel): Idle time processing should happen
   // here if there is budget for it.
   void DidDraw();
@@ -82,10 +84,10 @@ class FrameGenerator {
                       bool* may_contain_video) const;
 
   FrameGeneratorDelegate* delegate_;
-  scoped_refptr<SurfacesState> surfaces_state_;
+  scoped_refptr<surfaces::DisplayCompositor> display_compositor_;
   scoped_refptr<gpu::GpuChannelHost> gpu_channel_;
 
-  std::unique_ptr<DisplayCompositor> display_compositor_;
+  std::unique_ptr<surfaces::CompositorFrameSink> compositor_frame_sink_;
   gfx::AcceleratedWidget widget_ = gfx::kNullAcceleratedWidget;
 
   // The region that needs to be redrawn next time the compositor frame is