PPAPI: Make blocking completion callbacks work.

ppapi/shared_impl/ppapi_globals.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_PPAPI_GLOBALS_H_
 #define PPAPI_SHARED_IMPL_PPAPI_GLOBALS_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/threading/thread_local.h"  // For testing purposes only.
 #include "ppapi/c/dev/ppb_console_dev.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_module.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/ppapi_shared_export.h"
 
 namespace base {
 class Lock;
+class MessageLoopProxy;
 }
 
 namespace ppapi {
 
 class CallbackTracker;
 class FunctionGroupBase;
 class ResourceTracker;
 class VarTracker;
 
 // Abstract base class
@@ skipping 58 matching lines @@
                                       const std::string& value) = 0;
 
   // Returns the function object corresponding to the given ID, or NULL if
   // there isn't one.
   virtual FunctionGroupBase* GetFunctionAPI(PP_Instance inst, ApiID id) = 0;
 
   // Returns the PP_Module associated with the given PP_Instance, or 0 on
   // failure.
   virtual PP_Module GetModuleForInstance(PP_Instance instance) = 0;
 
+  base::MessageLoopProxy* GetMainThreadMessageLoop();
+
   virtual bool IsHostGlobals() const;
   virtual bool IsPluginGlobals() const;
 
  private:
   // Return the thread-local pointer which is used only for unit testing. It
   // should always be NULL when running in production. It allows separate
   // threads to have distinct "globals".
   static PpapiGlobals* GetThreadLocalPointer();
 
   static PpapiGlobals* ppapi_globals_;
 
   DISALLOW_COPY_AND_ASSIGN(PpapiGlobals);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_PPAPI_GLOBALS_H_