[cc] Plumb BeginFrameAcks through SurfaceManager to DisplayScheduler.

cc/surfaces/surface_manager.cc

Index: cc/surfaces/surface_manager.cc
diff --git a/cc/surfaces/surface_manager.cc b/cc/surfaces/surface_manager.cc
index cbdb78c5ea4a061887bcfc14fb2f627904fafd3f..fdd2960c7fea87a852c6558d1889865b71285849 100644
--- a/cc/surfaces/surface_manager.cc
+++ b/cc/surfaces/surface_manager.cc
@@ -118,6 +118,8 @@ std::unique_ptr<Surface> SurfaceManager::CreateSurface(
 void SurfaceManager::DestroySurface(std::unique_ptr<Surface> surface) {
   DCHECK(thread_checker_.CalledOnValidThread());
   surface->set_destroyed(true);
+  for (auto& observer : observer_list_)
+    observer.OnSurfaceDestroyed(surface->surface_id());
   surfaces_to_destroy_.push_back(std::move(surface));
   GarbageCollectSurfaces();
 }
@@ -498,6 +500,20 @@ void SurfaceManager::SurfaceDiscarded(Surface* surface) {
     dependency_tracker_->OnSurfaceDiscarded(surface);
 }
 
+void SurfaceManager::SurfaceReceivedBeginFrame(const SurfaceId& surface_id,
+                                               const BeginFrameArgs& args) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto& observer : observer_list_)
+    observer.OnSurfaceReceivedBeginFrame(surface_id, args);
+}
+
+void SurfaceManager::SurfaceFinishedBeginFrame(const SurfaceId& surface_id,
+                                               const BeginFrameAck& ack) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto& observer : observer_list_)
+    observer.OnSurfaceFinishedBeginFrame(surface_id, ack);
+}
+
 void SurfaceManager::UnregisterSurface(const SurfaceId& surface_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SurfaceMap::iterator it = surface_map_.find(surface_id);