Support using TrackedCallbacks as hints to determine the handling thread of resource reply messages

ppapi/proxy/ppb_message_loop_proxy.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_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 #define PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
@@ skipping 45 matching lines @@
 
   // Handles posting to the message loop if there is one, or the pending queue
   // if there isn't.
   // NOTE: The given closure will be run *WITHOUT* acquiring the Proxy lock.
   //       This only makes sense for user code and completely thread-safe
   //       proxy operations (e.g., MessageLoop::QuitClosure).
   virtual void PostClosure(const tracked_objects::Location& from_here,
                            const base::Closure& closure,
                            int64 delay_ms) OVERRIDE;
 
+  virtual base::MessageLoopProxy* GetMessageLoopProxy() OVERRIDE;
+
   // TLS destructor function.
   static void ReleaseMessageLoop(void* value);
 
   // Created when we attach to the current thread, since MessageLoop assumes
   // that it's created on the thread it will run on. NULL for the main thread
   // loop, since that's owned by somebody else. This is needed for Run and Quit.
   // Any time we post tasks, we should post them using loop_proxy_.
   scoped_ptr<base::MessageLoop> loop_;
   scoped_refptr<base::MessageLoopProxy> loop_proxy_;
 
@@ skipping 26 matching lines @@
   static const PPB_MessageLoop_1_0* GetInterface();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PPB_MessageLoop_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_