cc: Hook vsync time source to output surface

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index e69291d1d3c5c9106244e7a19db2679cd5aa4e42..edf26c57cbafc530d3a63b09ae302625eb4f9f18 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -48,6 +48,7 @@ class LayerTreeHostImplClient {
   virtual void OnSwapBuffersCompleteOnImplThread() = 0;
   virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
                                         base::TimeDelta interval) = 0;
+  virtual void DidVSync(base::TimeTicks frame_time) = 0;
   virtual void OnCanDrawStateChanged(bool can_draw) = 0;
   virtual void OnHasPendingTreeStateChanged(bool has_pending_tree) = 0;
   virtual void SetNeedsRedrawOnImplThread() = 0;
@@ -176,6 +177,7 @@ class CC_EXPORT LayerTreeHostImpl : public InputHandlerClient,
   // OutputSurfaceClient implementation.
   virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
                                         base::TimeDelta interval) OVERRIDE;
+  virtual void DidVSync(base::TimeTicks frame_time) OVERRIDE;
   virtual void OnSendFrameToParentCompositorAck(const CompositorFrameAck& ack)
       OVERRIDE;
 
@@ -199,6 +201,7 @@ class CC_EXPORT LayerTreeHostImpl : public InputHandlerClient,
   const RendererCapabilities& GetRendererCapabilities() const;
 
   virtual bool SwapBuffers();
+  void EnableVSyncNotification(bool enable);
 
   void Readback(void* pixels, gfx::Rect rect_in_device_viewport);