PPAPI: Make blocking completion callbacks work.

ppapi/shared_impl/ppb_graphics_3d_shared.h

 // 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 PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_
 #define PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ppapi/c/pp_completion_callback.h"
@@ skipping 18 matching lines @@
       public thunk::PPB_Graphics3D_API {
  public:
   // Resource overrides.
   virtual thunk::PPB_Graphics3D_API* AsPPB_Graphics3D_API() OVERRIDE;
 
   // PPB_Graphics3D_API implementation.
   virtual int32_t GetAttribs(int32_t attrib_list[]) OVERRIDE;
   virtual int32_t SetAttribs(const int32_t attrib_list[]) OVERRIDE;
   virtual int32_t GetError() OVERRIDE;
   virtual int32_t ResizeBuffers(int32_t width, int32_t height) OVERRIDE;
-  virtual int32_t SwapBuffers(PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t SwapBuffers(scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual void* MapTexSubImage2DCHROMIUM(GLenum target,
                                          GLint level,
                                          GLint xoffset,
                                          GLint yoffset,
                                          GLsizei width,
                                          GLsizei height,
                                          GLenum format,
                                          GLenum type,
                                          GLenum access) OVERRIDE;
   virtual void UnmapTexSubImage2DCHROMIUM(const void* mem) OVERRIDE;
@@ skipping 27 matching lines @@
   // Callback that needs to be executed when swap-buffers is completed.
   scoped_refptr<TrackedCallback> swap_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_Graphics3D_Shared);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_