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 37e7c5352b0db92479aa8e49e6c04431cca1a8a7..fdd7e57b9a1bd857ba13aec60b3ce16d9fb00f32 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -87,8 +87,6 @@ Scheduler::Scheduler(
       primary_frame_source_internal_(external_begin_frame_source.Pass()),
       background_frame_source_internal_(),
       vsync_observer_(NULL),
-      authoritative_vsync_interval_(base::TimeDelta()),
-      last_vsync_timebase_(base::TimeTicks()),
       throttle_frame_production_(scheduler_settings.throttle_frame_production),
       settings_(scheduler_settings),
       client_(client),
@@ -148,8 +146,18 @@ 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()) {
@@ -438,12 +446,6 @@ 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);
-}
-
 // BeginRetroFrame is called for BeginFrames that we've deferred because
 // the scheduler was in the middle of processing a previous BeginFrame.
 void Scheduler::BeginRetroFrame() {