Enqueuing new frames in a Surface should cause Displays to reaggregate it

cc/surfaces/surface_damage_observer.h

Index: cc/surfaces/surface_damage_observer.h
diff --git a/cc/surfaces/surface_damage_observer.h b/cc/surfaces/surface_damage_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..379c9f75ee47420e28e1fb02167a03de939ee635
--- /dev/null
+++ b/cc/surfaces/surface_damage_observer.h
@@ -0,0 +1,19 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CC_SURFACES_SURFACE_DAMAGE_OBSERVER_H_
+#define CC_SURFACES_SURFACE_DAMAGE_OBSERVER_H_
+
+#include "cc/surfaces/surface_id.h"
+
+namespace cc {
+
+class SurfaceDamageObserver {
+ public:
+  virtual void OnSurfaceDamaged(SurfaceId surface_id) = 0;
+};
+
+}  // namespace cc
+
+#endif  // CC_SURFACES_SURFACE_DAMAGE_OBSERVER_H_