PPAPI: Force async callback invocation option.

ppapi/proxy/ppb_surface_3d_proxy.cc

 // Copyright (c) 2011 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/proxy/ppb_surface_3d_proxy.h"
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/dev/ppb_surface_3d_dev.h"
@@ skipping 159 matching lines @@
 
   EnterFunctionNoLock<ResourceCreationAPI> enter(instance, true);
   if (enter.succeeded()) {
     result->SetHostResource(
         instance,
         enter.functions()->CreateSurface3D(instance, config, &attribs.front()));
   }
 }
 
 void PPB_Surface3D_Proxy::OnMsgSwapBuffers(const HostResource& surface_3d) {
-  CompletionCallback callback = callback_factory_.NewCallback(
+  CompletionCallback callback = callback_factory_.NewOptionalCallback(
       &PPB_Surface3D_Proxy::SendSwapBuffersACKToPlugin, surface_3d);
 
   EnterHostFromHostResource<PPB_Surface3D_API> enter(surface_3d);
   int32_t result = PP_ERROR_BADRESOURCE;
   if (enter.succeeded())
     result = enter.object()->SwapBuffers(callback.pp_completion_callback());
   if (result != PP_OK_COMPLETIONPENDING) {
     // There was some error, so we won't get a flush callback. We need to now
     // issue the ACK to the plugin hears about the error. This will also clean
     // up the data associated with the callback.
@@ skipping 10 matching lines @@
 
 void PPB_Surface3D_Proxy::SendSwapBuffersACKToPlugin(
     int32_t result,
     const HostResource& surface_3d) {
   dispatcher()->Send(new PpapiMsg_PPBSurface3D_SwapBuffersACK(
       INTERFACE_ID_PPB_SURFACE_3D, surface_3d, result));
 }
 
 }  // namespace proxy
 }  // namespace pp