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 c37250e85cefe7592f5b41745ff9d0b52a5ffd57..2288169ecde077c80dc44fe911097a87924f1869 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -401,6 +401,11 @@ 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(),