Add DisplayScheduler to enable BeginFrame-based scheduling of surfaces.

cc/surfaces/display.h

Index: cc/surfaces/display.h
diff --git a/cc/surfaces/display.h b/cc/surfaces/display.h
index 59355346e26f99e678abd5d0899a52d6d6799fac..c3b0bcb359d6072abdee45b64f59ee4e76711de8 100644
--- a/cc/surfaces/display.h
+++ b/cc/surfaces/display.h
@@ -23,6 +23,7 @@ namespace cc {
 class BlockingTaskRunner;
 class DirectRenderer;
 class DisplayClient;
+class DisplayScheduler;
 class OutputSurface;
 class ResourceProvider;
 class SharedBitmapManager;
@@ -45,7 +46,8 @@ class CC_SURFACES_EXPORT Display : public OutputSurfaceClient,
           gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager);
   ~Display() override;
 
-  bool Initialize(scoped_ptr<OutputSurface> output_surface);
+  bool Initialize(scoped_ptr<OutputSurface> output_surface,
+                  DisplayScheduler* scheduler);
 
   // device_scale_factor is used to communicate to the external window system
   // what scale this was rendered at.
@@ -95,6 +97,7 @@ class CC_SURFACES_EXPORT Display : public OutputSurfaceClient,
   float device_scale_factor_;
   LayerTreeSettings settings_;
   scoped_ptr<OutputSurface> output_surface_;
+  DisplayScheduler* scheduler_;
   scoped_ptr<ResourceProvider> resource_provider_;
   scoped_ptr<SurfaceAggregator> aggregator_;
   scoped_ptr<DirectRenderer> renderer_;