PPAPI: Make blocking completion callbacks work.

webkit/plugins/ppapi/ppb_layer_compositor_impl.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 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 WEBKIT_PLUGINS_PPAPI_PPB_LAYER_COMPOSITOR_IMPL_H_
 #define WEBKIT_PLUGINS_PPAPI_PPB_LAYER_COMPOSITOR_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "ppapi/thunk/ppb_layer_compositor_api.h"
 #include "ppapi/shared_impl/resource.h"
 
@@ skipping 14 matching lines @@
   // Resource override.
   virtual PPB_LayerCompositor_API* AsPPB_LayerCompositor_API();
 
   // PPB_LayerCompositor_API implementation.
   virtual PP_Bool AddLayer(PP_Resource layer) OVERRIDE;
   virtual void RemoveLayer(PP_Resource layer) OVERRIDE;
   virtual void SetZIndex(PP_Resource layer, int32_t index) OVERRIDE;
   virtual void SetRect(PP_Resource layer, const PP_Rect* rect) OVERRIDE;
   virtual void SetDisplay(PP_Resource layer, PP_Bool is_displayed) OVERRIDE;
   virtual void MarkAsDirty(PP_Resource layer) OVERRIDE;
-  virtual int32_t SwapBuffers(PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t SwapBuffers(
+      scoped_refptr< ::ppapi::TrackedCallback> callback) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PPB_LayerCompositor_Impl);
 };
 
 }  // namespace ppapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_PPAPI_PPB_LAYER_COMPOSITOR_IMPL_H_