Fix scrollbar fade animation scheduling.

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..8d3b5a5f467b4ed76acfad5ec923978656baa6cb 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -131,7 +131,7 @@ class CC_EXPORT LayerTreeHostImpl
   virtual void DidChangeTopControlsPosition() OVERRIDE;
   virtual bool HaveRootScrollLayer() const OVERRIDE;
 
-  void StartScrollbarAnimation(base::TimeTicks now);
+  void StartScrollbarAnimation();
 
   struct CC_EXPORT FrameData : public RenderPassSink {
     FrameData();
@@ -370,6 +370,9 @@ class CC_EXPORT LayerTreeHostImpl
   base::TimeTicks CurrentFrameTimeTicks();
   base::Time CurrentFrameTime();
 
+  base::TimeTicks CurrentPhysicalTimeTicks() const;
+  void SetCurrentPhysicalTimeTicksForTest(base::TimeTicks fake_time);
+
   scoped_ptr<base::Value> AsValue() const;
   scoped_ptr<base::Value> ActivationStateAsValue() const;
 
@@ -438,6 +441,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   static LayerImpl* GetNonCompositedContentLayerRecursive(LayerImpl* layer);
 
+  void UpdateCurrentFrameTime(base::TimeTicks* ticks, base::Time* now) const;
+
   void StartScrollbarAnimationRecursive(LayerImpl* layer, base::TimeTicks time);
 
   scoped_ptr<OutputSurface> output_surface_;
@@ -527,6 +532,7 @@ class CC_EXPORT LayerTreeHostImpl
 
   base::TimeTicks current_frame_timeticks_;
   base::Time current_frame_time_;
+  base::TimeTicks fake_current_physical_time_for_test_;
 
   scoped_ptr<AnimationRegistrar> animation_registrar_;