Add DisplayScheduler for Surfaces

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index d52141fa1f1fc5ed5136be334fe47a3168bed146..9ca056f9ebb452fd719ca40589b5df146ce7be1b 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -128,8 +128,18 @@ base::TimeTicks Scheduler::Now() const {
   return now;
 }
 
+void Scheduler::SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) {
+  authoritative_vsync_interval_ = interval;
+  if (vsync_observer_)
+    vsync_observer_->OnUpdateVSyncParameters(last_vsync_timebase_, interval);
+}
+
 void Scheduler::CommitVSyncParameters(base::TimeTicks timebase,
                                       base::TimeDelta interval) {
+  TRACE_EVENT2("cc", "Scheduler::CommitVSyncParameters", "timebase",
+               (timebase - base::TimeTicks()).InSecondsF(), "interval",
+               interval.InSecondsF());
+
   if (authoritative_vsync_interval_ != base::TimeDelta()) {
     interval = authoritative_vsync_interval_;
   } else if (interval == base::TimeDelta()) {
@@ -394,12 +404,6 @@ void Scheduler::SetChildrenNeedBeginFrames(bool children_need_begin_frames) {
   ProcessScheduledActions();
 }
 
-void Scheduler::SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) {
-  authoritative_vsync_interval_ = interval;
-  if (vsync_observer_)
-    vsync_observer_->OnUpdateVSyncParameters(last_vsync_timebase_, interval);
-}
-
 void Scheduler::OnDrawForOutputSurface() {
   DCHECK(settings_.using_synchronous_renderer_compositor);
   DCHECK_EQ(state_machine_.begin_impl_frame_state(),