PPAPI: Make blocking completion callbacks work.

ppapi/shared_impl/ppb_graphics_3d_shared.cc

 // 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.
 
 #include "ppapi/shared_impl/ppb_graphics_3d_shared.h"
 
 #include "base/logging.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "gpu/command_buffer/client/transfer_buffer.h"
@@ skipping 37 matching lines @@
 
 int32_t PPB_Graphics3D_Shared::ResizeBuffers(int32_t width, int32_t height) {
   if ((width < 0) || (height < 0))
     return PP_ERROR_BADARGUMENT;
 
   gles2_impl()->ResizeCHROMIUM(width, height);
   // TODO(alokp): Check if resize succeeded and return appropriate error code.
   return PP_OK;
 }
 
-int32_t PPB_Graphics3D_Shared::SwapBuffers(PP_CompletionCallback callback) {
-  if (!callback.func) {
-    // Blocking SwapBuffers isn't supported (since we have to be on the main
-    // thread).
-    return PP_ERROR_BADARGUMENT;
-  }
-
+int32_t PPB_Graphics3D_Shared::SwapBuffers(
+    scoped_refptr<TrackedCallback> callback) {
   if (HasPendingSwap()) {
     // Already a pending SwapBuffers that hasn't returned yet.
     return PP_ERROR_INPROGRESS;
   }
 
-  swap_callback_ = new TrackedCallback(this, callback);
+  swap_callback_ = callback;
   return DoSwapBuffers();
 }
 
 void* PPB_Graphics3D_Shared::MapTexSubImage2DCHROMIUM(GLenum target,
                                                       GLint level,
                                                       GLint xoffset,
                                                       GLint yoffset,
                                                       GLsizei width,
                                                       GLsizei height,
                                                       GLenum format,
@@ skipping 53 matching lines @@
 }
 
 void PPB_Graphics3D_Shared::DestroyGLES2Impl() {
   gles2_impl_.reset();
   transfer_buffer_.reset();
   gles2_helper_.reset();
 }
 
 }  // namespace ppapi