Provide a vsync notification to the renderer

cc/layer_tree_host_impl.h

Index: cc/layer_tree_host_impl.h
diff --git a/cc/layer_tree_host_impl.h b/cc/layer_tree_host_impl.h
index cac5d5901a544f27fcb436e24f01638728166160..f6ad346a6356a6b14c3c69fb00b7b160c2d965cd 100644
--- a/cc/layer_tree_host_impl.h
+++ b/cc/layer_tree_host_impl.h
@@ -47,6 +47,7 @@ public:
     virtual void didLoseOutputSurfaceOnImplThread() = 0;
     virtual void onSwapBuffersCompleteOnImplThread() = 0;
     virtual void onVSyncParametersChanged(base::TimeTicks timebase, base::TimeDelta interval) = 0;
+    virtual void didVSync(base::TimeTicks frameTime) = 0;
     virtual void onCanDrawStateChanged(bool canDraw) = 0;
     virtual void onHasPendingTreeStateChanged(bool hasPendingTree) = 0;
     virtual void setNeedsRedrawOnImplThread() = 0;
@@ -141,6 +142,7 @@ public:
 
     // OutputSurfaceClient implementation.
     virtual void OnVSyncParametersChanged(base::TimeTicks timebase, base::TimeDelta interval) OVERRIDE;
+    virtual void DidVSync(base::TimeTicks frameTime) OVERRIDE;
     virtual void OnSendFrameToParentCompositorAck(const CompositorFrameAck&) OVERRIDE;
 
     // Called from LayerTreeImpl.
@@ -149,6 +151,7 @@ public:
     // Implementation
     bool canDraw();
     OutputSurface* outputSurface() const;
+    void enableVSyncNotification(bool enable);
 
     std::string layerTreeAsText() const;
     std::string layerTreeAsJson() const;