Unified BeginFrame scheduling

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 34717a04acd7469c273319765d72666d7167ee8d..e90b6528f701e5e45626c33978f7fed6284b1798 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -46,6 +46,7 @@ class SchedulerClient {
   virtual base::TimeDelta BeginMainFrameToCommitDurationEstimate() = 0;
   virtual base::TimeDelta CommitToActivateDurationEstimate() = 0;
   virtual void DidBeginImplFrameDeadline() = 0;
+  virtual void SendBeginFrameToChildren(const BeginFrameArgs& args) = 0;
 
  protected:
   virtual ~SchedulerClient() {}
@@ -134,6 +135,11 @@ class CC_EXPORT Scheduler {
     state_machine_.SetContinuousPainting(continuous_painting);
   }
 
+  // SetChildrenNeedBeginFrames() is only used when this Scheduler is acting
+  // as the publisher.
+  void SetChildrenNeedBeginFrames(bool need_begin_frame);
+  void SetAuthoritativeVSyncInterval(base::TimeDelta interval);
+
  protected:
   class CC_EXPORT SyntheticBeginFrameSource : public TimeSourceClient {
    public:
@@ -177,6 +183,9 @@ class CC_EXPORT Scheduler {
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   base::TimeDelta vsync_interval_;
+  base::TimeDelta authoritative_vsync_interval_;
+  base::TimeTicks last_timebase_;
+
   base::TimeDelta estimated_parent_draw_time_;
 
   bool last_set_needs_begin_frame_;