Chrome-side of making CallOnMainThread use a completion callback....

webkit/glue/plugins/pepper_plugin_module.cc

 // Copyright (c) 2010 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 "webkit/glue/plugins/pepper_plugin_module.h"
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/message_loop.h"
@@ skipping 77 matching lines @@
 }
 
 void MemFree(void* ptr) {
   free(ptr);
 }
 
 double GetTime() {
   return base::Time::Now().ToDoubleT();
 }
 
-void CallOnMainThread(int delay_in_msec, void (*func)(void*), void* context) {
+void CallOnMainThread(int delay_in_msec,
+                      PP_CompletionCallback callback,
+                      int32_t result) {
   GetMainThreadMessageLoop()->PostDelayedTask(
       FROM_HERE,
-      NewRunnableFunction(func, context),
+      NewRunnableFunction(callback.func, callback.user_data, result),
       delay_in_msec);
 }
 
 const PPB_Core core_interface = {
   &AddRefResource,
   &ReleaseResource,
   &MemAlloc,
   &MemFree,
   &GetTime,
   &CallOnMainThread
@@ skipping 221 matching lines @@
 
 void PluginModule::InstanceCreated(PluginInstance* instance) {
   instances_.insert(instance);
 }
 
 void PluginModule::InstanceDeleted(PluginInstance* instance) {
   instances_.erase(instance);
 }
 
 }  // namespace pepper