content: Cleanup class/struct forward declarations

content/public/renderer/render_thread.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 CONTENT_PUBLIC_RENDERER_RENDER_THREAD_H_
 #define CONTENT_PUBLIC_RENDERER_RENDER_THREAD_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/user_metrics_action.h"
 #include "content/common/content_export.h"
 #include "content/public/child/child_thread.h"
 #include "ipc/ipc_channel_proxy.h"
 
 class GURL;
 
 namespace base {
-class MessageLoop;
 class WaitableEvent;
 }
 
 namespace cc {
 class SharedBitmapManager;
 }
 
 namespace IPC {
 class MessageFilter;
 class SyncChannel;
@@ skipping 70 matching lines @@
   // proxy servers.
   virtual bool ResolveProxy(const GURL& url, std::string* proxy_list) = 0;
 
   // Gets the shutdown event for the process.
   virtual base::WaitableEvent* GetShutdownEvent() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_RENDER_THREAD_H_