cc: Add main frame timing info to frame timing tracker.

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 18250c045a4bc46859089747525fe1c44a4da784..304ff385fee1af2ab660a070368ed80f3245a8fd 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -111,6 +111,7 @@ class LayerTreeHostImplClient {
                                                     base::TimeDelta delay) = 0;
   virtual void DidActivateSyncTree() = 0;
   virtual void DidPrepareTiles() = 0;
+  virtual base::TimeTicks GetNextPredictedRequestAnimationFrameTime() const = 0;
 
   // Called when page scale animation has completed on the impl thread.
   virtual void DidCompletePageScaleAnimationOnImplThread() = 0;
@@ -518,6 +519,9 @@ class CC_EXPORT LayerTreeHostImpl
     return frame_timing_tracker_.get();
   }
 
+  void SetCurrentRequestAnimationFrameTime(base::TimeTicks frame_time);
+  void RecordMainFrameTiming();

[mithro-old, 2015/03/20 02:17:54]

This method should definitely be taking a BeginFrameArgs not a base::TimeTicks.

SetCurrentRequestAnimationFrameTime is a bit confusing because there is the
animation frame time used for the impl thread and the animation frame time used
for the main thread which are not equal. I can quickly see this value getting
used in the wrong places.

[vmpstr, 2015/03/20 18:47:26]

Ok, I will work on passing BeginFrameArgs here instead. My, again clearly
flawed, understanding was that the impl thread time and the raf animation time
was in fact the same time. Please let me know where they diverge.

+
  protected:
   LayerTreeHostImpl(
       const LayerTreeSettings& settings,
@@ -735,6 +739,7 @@ class CC_EXPORT LayerTreeHostImpl
   bool is_likely_to_require_a_draw_;
 
   scoped_ptr<FrameTimingTracker> frame_timing_tracker_;
+  base::TimeTicks request_animation_frame_time_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };