Implement service-side surface synchronization

cc/surfaces/surface_factory.h

Index: cc/surfaces/surface_factory.h
diff --git a/cc/surfaces/surface_factory.h b/cc/surfaces/surface_factory.h
index f77fdc48e589344e5e60c2b64a58068408560cf2..4a9f6afe2548ab8eb0a873954b51eda5204a218f 100644
--- a/cc/surfaces/surface_factory.h
+++ b/cc/surfaces/surface_factory.h
@@ -13,6 +13,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "cc/output/compositor_frame.h"
+#include "cc/surfaces/pending_frame_observer.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_resource_holder.h"
 #include "cc/surfaces/surface_sequence.h"
@@ -32,14 +33,14 @@ class SurfaceManager;
 // particular factory will be returned to that factory's client when they are no
 // longer being used. This is the only class most users of surfaces will need to
 // directly interact with.
-class CC_SURFACES_EXPORT SurfaceFactory {
+class CC_SURFACES_EXPORT SurfaceFactory : public PendingFrameObserver {
  public:
   using DrawCallback = base::Callback<void()>;
 
   SurfaceFactory(const FrameSinkId& frame_sink_id,
                  SurfaceManager* manager,
                  SurfaceFactoryClient* client);
-  ~SurfaceFactory();
+  ~SurfaceFactory() override;
 
   const FrameSinkId& frame_sink_id() const { return frame_sink_id_; }
 
@@ -78,6 +79,8 @@ class CC_SURFACES_EXPORT SurfaceFactory {
 
   SurfaceManager* manager() { return manager_; }
 
+  Surface* current_surface_for_testing() { return current_surface_.get(); }
+
   // This can be set to false if resources from this SurfaceFactory don't need
   // to have sync points set on them when returned from the Display, for
   // example if the Display shares a context with the creator.
@@ -89,6 +92,14 @@ class CC_SURFACES_EXPORT SurfaceFactory {
   void DidDestroySurfaceManager() { manager_ = nullptr; }
 
  private:
+  // PendingFrameObserver implementation.
+  void OnSurfaceActivated(Surface* pending_surface) override;
+  void OnSurfaceDependenciesChanged(
+      Surface* pending_surface,
+      const SurfaceDependencies& added_dependencies,
+      const SurfaceDependencies& removed_dependencies) override;
+  void OnSurfaceDiscarded(Surface* pending_surface) override;
+
   std::unique_ptr<Surface> Create(const LocalSurfaceId& local_surface_id);
   void Destroy(std::unique_ptr<Surface> surface);