Change LayerHostImpl to use frame time from BeginFrameArgs rather than ::Now()

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 255128b04b45df40ed030df1886a1f434b2126ac..be87b778434848a3759ba7c8cbab97420e1cab4e 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -388,10 +388,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   void SetTreePriority(TreePriority priority);
 
-  void ResetCurrentFrameTimeForNextFrame();
-  virtual base::TimeTicks CurrentFrameTimeTicks();
-
-  virtual base::TimeTicks CurrentPhysicalTimeTicks() const;
+  virtual base::TimeTicks CurrentFrameTimeTicks() const;
+  virtual void OverrideCurrentFrameTime(base::TimeTicks frame_time);
 
   scoped_ptr<base::Value> AsValue() const { return AsValueWithFrame(NULL); }
   scoped_ptr<base::Value> AsValueWithFrame(FrameData* frame) const;
@@ -637,7 +635,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   gfx::Rect viewport_damage_rect_;
 
-  base::TimeTicks current_frame_timeticks_;
+  BeginFrameArgs current_frame_args_;
+  BeginFrameArgs last_frame_args_;
 
   scoped_ptr<AnimationRegistrar> animation_registrar_;