[cc] Add and use BeginFrameAck for DidFinishFrame.

cc/surfaces/display_scheduler.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_SURFACES_DISPLAY_SCHEDULER_H_
 #define CC_SURFACES_DISPLAY_SCHEDULER_H_
 
 #include <memory>
 
 #include "base/cancelable_callback.h"
@@ skipping 37 matching lines @@
 
   void OutputSurfaceLost();
 
   // BeginFrameObserverBase implementation
   bool OnBeginFrameDerivedImpl(const BeginFrameArgs& args) override;
   void OnBeginFrameSourcePausedChanged(bool paused) override;
 
  protected:
   base::TimeTicks DesiredBeginFrameDeadlineTime();
   virtual void ScheduleBeginFrameDeadline();
-  void AttemptDrawAndSwap();
+  bool AttemptDrawAndSwap();
   void OnBeginFrameDeadline();
-  void DrawAndSwap();
+  bool DrawAndSwap();
   void StartObservingBeginFrames();
   void StopObservingBeginFrames();
   bool ShouldDraw();
+  void DidFinishFrame(bool did_draw);
 
   DisplaySchedulerClient* client_;
   BeginFrameSource* begin_frame_source_;
   base::SingleThreadTaskRunner* task_runner_;
 
   BeginFrameArgs current_begin_frame_args_;
   base::Closure begin_frame_deadline_closure_;
   base::CancelableClosure begin_frame_deadline_task_;
   base::TimeTicks begin_frame_deadline_task_time_;
 
@@ skipping 24 matching lines @@
 
   base::WeakPtrFactory<DisplayScheduler> weak_ptr_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DisplayScheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_DISPLAY_SCHEDULER_H_