cc: Emulate BeginFrame in OutputSurfaces that don't support it natively

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 e05e45bbfeac56854e6a2bf8cb0b8714b918c225..8129dc2be7a88bbb7a869d200aec3013b427ff6f 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -54,8 +54,6 @@ class LayerTreeHostImplClient {
       scoped_refptr<ContextProvider> offscreen_context_provider) = 0;
   virtual void DidLoseOutputSurfaceOnImplThread() = 0;
   virtual void OnSwapBuffersCompleteOnImplThread() = 0;
-  virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
-                                        base::TimeDelta interval) = 0;
   virtual void BeginFrameOnImplThread(base::TimeTicks frame_time) = 0;
   virtual void OnCanDrawStateChanged(bool can_draw) = 0;
   virtual void OnHasPendingTreeStateChanged(bool has_pending_tree) = 0;
@@ -183,8 +181,6 @@ class CC_EXPORT LayerTreeHostImpl
   virtual float DeviceScaleFactor() const OVERRIDE;
   virtual const LayerTreeSettings& Settings() const OVERRIDE;
  public:
-  virtual void DidLoseOutputSurface() OVERRIDE;
-  virtual void OnSwapBuffersComplete(const CompositorFrameAck* ack) OVERRIDE;
   virtual void SetFullRootLayerDamage() OVERRIDE;
   virtual void SetManagedMemoryPolicy(const ManagedMemoryPolicy& policy)
       OVERRIDE;
@@ -204,12 +200,12 @@ class CC_EXPORT LayerTreeHostImpl
   virtual bool DeferredInitialize(
       scoped_refptr<ContextProvider> offscreen_context_provider) OVERRIDE;
   virtual void SetNeedsRedrawRect(gfx::Rect rect) OVERRIDE;
-  virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
-                                        base::TimeDelta interval) OVERRIDE;
   virtual void BeginFrame(base::TimeTicks frame_time)
       OVERRIDE;
   virtual void SetExternalDrawConstraints(const gfx::Transform& transform,
                                           gfx::Rect viewport) OVERRIDE;
+  virtual void DidLoseOutputSurface() OVERRIDE;
+  virtual void OnSwapBuffersComplete(const CompositorFrameAck* ack) OVERRIDE;
 
   // Called from LayerTreeImpl.
   void OnCanDrawStateChangedForTree();