Allow cc::Scheduler begin frame source to be changed

cc/scheduler/scheduler.h

 // Copyright 2011 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_SCHEDULER_SCHEDULER_H_
 #define CC_SCHEDULER_SCHEDULER_H_
 
 #include <deque>
 #include <string>
 
@@ skipping 62 matching lines @@
 
   const SchedulerSettings& settings() const { return settings_; }
 
   void SetEstimatedParentDrawTime(base::TimeDelta draw_time);
 
   void SetVisible(bool visible);
   bool visible() { return state_machine_.visible(); }
   void SetCanDraw(bool can_draw);
   void NotifyReadyToActivate();
   void NotifyReadyToDraw();
+  void SetBeginFrameSource(BeginFrameSource* source);
 
   void SetNeedsBeginMainFrame();
   // Requests a single impl frame (after the current frame if there is one
   // active).
   void SetNeedsOneBeginImplFrame();
 
   void SetNeedsRedraw();
 
   void SetNeedsPrepareTiles();
 
@@ skipping 40 matching lines @@
   base::TimeTicks LastBeginImplFrameTime();
 
   void SetDeferCommits(bool defer_commits);
 
   scoped_ptr<base::trace_event::ConvertableToTraceFormat> AsValue() const;
   void AsValueInto(base::trace_event::TracedValue* value) const override;
 
   void SetChildrenNeedBeginFrames(bool children_need_begin_frames);
   void SetVideoNeedsBeginFrames(bool video_needs_begin_frames);
 
+  const BeginFrameSource* begin_frame_source() const {
+    return begin_frame_source_;
+  }
+
  protected:
   Scheduler(SchedulerClient* client,
             const SchedulerSettings& scheduler_settings,
             int layer_tree_host_id,
             base::SingleThreadTaskRunner* task_runner,
             BeginFrameSource* begin_frame_source,
             scoped_ptr<CompositorTimingHistory> compositor_timing_history);
 
   // Virtual for testing.
   virtual base::TimeTicks Now() const;
@@ skipping 62 matching lines @@
   }
 
   base::WeakPtrFactory<Scheduler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_H_