cc: Add SetChildrenNeedBeginFrames() & SendBeginFramesToChildren()

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 523c24651f2783b9f95d02fc862a6168f73e7ccf..46007500f74905692ff62c6749e2a49eeb3ef463 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -49,6 +49,7 @@ class SchedulerClient {
   virtual base::TimeDelta BeginMainFrameToCommitDurationEstimate() = 0;
   virtual base::TimeDelta CommitToActivateDurationEstimate() = 0;
   virtual void DidBeginImplFrameDeadline() = 0;
+  virtual void SendBeginFramesToChildren(const BeginFrameArgs& args) = 0;
 
  protected:
   virtual ~SchedulerClient() {}
@@ -94,6 +95,9 @@ class CC_EXPORT Scheduler : public BeginFrameObserverMixIn,
 
   ~Scheduler() override;
 
+  // BeginFrameObserverMixin
+  bool OnBeginFrameMixInDelegate(const BeginFrameArgs& args) override;
+
   // base::PowerObserver method.
   void OnPowerStateChange(bool on_battery_power) override;
 
@@ -166,8 +170,7 @@ class CC_EXPORT Scheduler : public BeginFrameObserverMixIn,
     state_machine_.SetContinuousPainting(continuous_painting);
   }
 
-  // BeginFrameObserverMixin
-  bool OnBeginFrameMixInDelegate(const BeginFrameArgs& args) override;
+  void SetChildrenNeedBeginFrames(bool children_need_begin_frames);
 
  protected:
   Scheduler(SchedulerClient* client,