Avoid destroying surface before the parent surface stops referencing it.

cc/surfaces/surface_manager.h

Index: cc/surfaces/surface_manager.h
diff --git a/cc/surfaces/surface_manager.h b/cc/surfaces/surface_manager.h
index 7515be51fdaf2d9dac42cc388447428f4fb5bfb8..66db9d90ee38df8e10e604dd75463ab3d6644f97 100644
--- a/cc/surfaces/surface_manager.h
+++ b/cc/surfaces/surface_manager.h
@@ -5,12 +5,17 @@
 #ifndef CC_SURFACES_SURFACE_MANAGER_H_
 #define CC_SURFACES_SURFACE_MANAGER_H_
 
+#include <list>
+#include <set>
+#include <vector>
+
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "cc/surfaces/surface_damage_observer.h"
 #include "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_sequence.h"
 #include "cc/surfaces/surfaces_export.h"
 
 namespace cc {
@@ -25,6 +30,10 @@ class CC_SURFACES_EXPORT SurfaceManager {
   void RegisterSurface(Surface* surface);
   void DeregisterSurface(SurfaceId surface_id);
 
+  // Destroy the Surface once a set of sequence numbers has been satisfied.
+  void DestroyOnSequence(scoped_ptr<Surface> surface,
+                         const std::set<SurfaceSequence>& dependency_set);
+
   Surface* GetSurfaceForId(SurfaceId surface_id);
 
   void AddObserver(SurfaceDamageObserver* obs) {
@@ -37,12 +46,27 @@ class CC_SURFACES_EXPORT SurfaceManager {
 
   void SurfaceModified(SurfaceId surface_id);
 
+  // A frame for a surface satisfies a set of sequence numbers.
+  void DidSatisfySequences(SurfaceId id, std::vector<uint32_t>* sequence);
+
  private:
+  void SearchForSatisfaction();
+
   typedef base::hash_map<SurfaceId, Surface*> SurfaceMap;
   SurfaceMap surface_map_;
   ObserverList<SurfaceDamageObserver> observer_list_;
   base::ThreadChecker thread_checker_;
 
+  // List of surfaces to be destroyed, along with what sequences they're still
+  // waiting on.
+  typedef std::list<std::pair<Surface*, std::set<SurfaceSequence>>>
+      SurfaceDestroyList;
+  SurfaceDestroyList surfaces_to_destroy_;
+
+  // Set of SurfaceSequences that have been satisfied by a frame but not yet
+  // waited on.
+  std::set<SurfaceSequence> satisfied_sequences_;
+
   DISALLOW_COPY_AND_ASSIGN(SurfaceManager);
 };