Remove CompositorObserver::OnCompositingEnded()

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 81a934550879bc91ea2e3d17bc273a65b206dbe4..212984fe2913e1db4005e4d3e55dcc507da2255a 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -525,15 +525,12 @@ void Compositor::DidFailToInitializeCompositorFrameSink() {
 
 void Compositor::DidCommit() {
   DCHECK(!IsLocked());
+  ++committed_frame_number_;

[varkha, 2017/03/27 19:41:52]

Yea, this I think could change the metric as measured. The intention was to see
how many frame commits actually make it to the hardware and are visible. It is
used in the metric that measures how smooth the animations are by keeping track
of how many frames are presented between the start and the end of a given
animation. 

   for (auto& observer : observer_list_)
     observer.OnCompositingDidCommit(this);
 }
 
-void Compositor::DidReceiveCompositorFrameAck() {
-  ++committed_frame_number_;
-  for (auto& observer : observer_list_)
-    observer.OnCompositingEnded(this);
-}
+void Compositor::DidReceiveCompositorFrameAck() {}
 
 void Compositor::DidSubmitCompositorFrame() {
   base::TimeTicks start_time = base::TimeTicks::Now();