[cc] Plumb BeginFrameAcks through SurfaceManager to DisplayScheduler.

cc/surfaces/surface_observer.h

 // Copyright 2016 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_OBSERVER_H_
 #define CC_SURFACES_SURFACE_OBSERVER_H_
 
 namespace cc {
 
+struct BeginFrameAck;
+struct BeginFrameArgs;
+class SurfaceId;
 class SurfaceInfo;
 
 class SurfaceObserver {
  public:
-  // Runs when a CompositorFrame is received for the given SurfaceInfo for the
+  // Runs when a CompositorFrame is activated for the given SurfaceInfo for the
   // first time.
   virtual void OnSurfaceCreated(const SurfaceInfo& surface_info) = 0;
 
-  // Runs when a Surface is damaged. *changed should be set to true if this
-  // causes a Display to be damaged.
-  virtual void OnSurfaceDamaged(const SurfaceId& surface_id, bool* changed) = 0;
+  // Runs when a Surface was marked to be destroyed.
+  virtual void OnSurfaceDestroyed(const SurfaceId& surface_id) = 0;
+
+  // Runs when a Surface is modified, e.g. when a CompositorFrame is
+  // activated, its producer confirms that no CompositorFrame will be submitted
+  // in response to a BeginFrame, or a CopyOutputRequest is issued.
+  //
+  // |ack.sequence_number| is only valid if called in response to a BeginFrame.
+  // |*changed| should be set to true if this causes a Display to be damaged.
+  virtual void OnSurfaceDamaged(const SurfaceId& surface_id,
+                                const BeginFrameAck& ack,
+                                bool* changed) = 0;
 
   // Called when a surface is garbage-collected.
   virtual void OnSurfaceDiscarded(const SurfaceId& surface_id) = 0;
+
+  // Runs when a Surface's CompositorFrame producer has received a BeginFrame
+  // and, thus, is expected to produce damage soon.
+  virtual void OnSurfaceDamageExpected(const SurfaceId& surface_id,
+                                       const BeginFrameArgs& args) = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_SURFACE_OBSERVER_H_