cc: Add support for sending BeginFrames for video.

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index d52141fa1f1fc5ed5136be334fe47a3168bed146..afbe36c75b3b1cb8b3048cb412eab3d9b11cc193 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -400,6 +400,11 @@ void Scheduler::SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) {
     vsync_observer_->OnUpdateVSyncParameters(last_vsync_timebase_, interval);
 }
 
+void Scheduler::SetVideoNeedsBeginFrames(bool video_needs_begin_frames) {
+  state_machine_.SetVideoNeedsBeginFrames(video_needs_begin_frames);
+  ProcessScheduledActions();
+}
+
 void Scheduler::OnDrawForOutputSurface() {
   DCHECK(settings_.using_synchronous_renderer_compositor);
   DCHECK_EQ(state_machine_.begin_impl_frame_state(),