Deliver IPC messages together with SwapCompositorFrame

cc/output/output_surface_client.h

 // Copyright 2012 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_OUTPUT_OUTPUT_SURFACE_CLIENT_H_
 #define CC_OUTPUT_OUTPUT_SURFACE_CLIENT_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
@@ skipping 30 matching lines @@
   virtual void SetExternalDrawConstraints(const gfx::Transform& transform,
                                           const gfx::Rect& viewport,
                                           const gfx::Rect& clip,
                                           bool valid_for_tile_management) = 0;
   virtual void SetMemoryPolicy(const ManagedMemoryPolicy& policy) = 0;
   // If set, |callback| will be called subsequent to each new tree activation,
   // regardless of the compositor visibility or damage. |callback| must remain
   // valid for the lifetime of the OutputSurfaceClient or until unregisted --
   // use SetTreeActivationCallback(base::Closure()) to unregister it.
   virtual void SetTreeActivationCallback(const base::Closure& callback) = 0;
+  virtual int GetSourceFrameNumber() = 0;
 
  protected:
   virtual ~OutputSurfaceClient() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_CLIENT_H_