[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 9875d04d29debce79e941266f16c4eff507e1ed6..d741645a40b516bb4fbf9541577c6375e1474058 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_)

[sunnyps, 2017/05/25 20:49:13]

nit: Why OnSurfaceDestroyed in addition to OnSurfaceDiscarded? Is it because
surfaces which are destroyed but not discarded may be drawn by other surfaces
but acks will not be submitted any more? I don't know if this difference is
important in practice.

[Eric Seckler, 2017/05/26 10:57:52]

I want to avoid waiting for destroyed Surfaces (that haven't yet been gc-ed for
some reason), since they won't receive a SurfaceModified (and with that, a
BeginFrameAck) for any potentially pending BeginFrame.

I'm not sure in which situations a destroyed Surface may actually remain alive,
but making assumptions about this seems dangerous anyway (?).

Keeping as-is for now.

+    observer.OnSurfaceDestroyed(surface->surface_id());
   surfaces_to_destroy_.push_back(std::move(surface));
   GarbageCollectSurfaces();
 }
@@ -453,11 +455,12 @@ Surface* SurfaceManager::GetSurfaceForId(const SurfaceId& surface_id) {
   return it->second;
 }
 
-bool SurfaceManager::SurfaceModified(const SurfaceId& surface_id) {
+bool SurfaceManager::SurfaceModified(const SurfaceId& surface_id,
+                                     const BeginFrameAck& ack) {
   CHECK(thread_checker_.CalledOnValidThread());
   bool changed = false;
   for (auto& observer : observer_list_)
-    observer.OnSurfaceDamaged(surface_id, &changed);
+    observer.OnSurfaceDamaged(surface_id, ack, &changed);
   return changed;
 }
 
@@ -500,6 +503,13 @@ void SurfaceManager::SurfaceDiscarded(Surface* surface) {
     dependency_tracker_->OnSurfaceDiscarded(surface);
 }
 
+void SurfaceManager::SurfaceDamageExpected(const SurfaceId& surface_id,
+                                           const BeginFrameArgs& args) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto& observer : observer_list_)
+    observer.OnSurfaceDamageExpected(surface_id, args);
+}
+
 void SurfaceManager::UnregisterSurface(const SurfaceId& surface_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SurfaceMap::iterator it = surface_map_.find(surface_id);