Remove obviously unneeded forward declarations in chrome/browser/[abef]*/*.h.

chrome/browser/extensions/extension_message_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_
 #pragma once
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/lock.h"
 #include "base/ref_counted.h"
 #include "chrome/common/notification_registrar.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/extensions/extension_devtools_manager.h"
 #include "ipc/ipc_message.h"
 
 class GURL;
-class MessageLoop;
 class Profile;
 class RenderProcessHost;
 class ResourceMessageFilter;
 class TabContents;
-class URLRequestContext;
 
 // This class manages message and event passing between renderer processes.
 // It maintains a list of processes that are listening to events and a set of
 // open channels.
 //
 // Messaging works this way:
 // - An extension-owned script context (like a toolstrip or a content script)
 // adds an event listener to the "onConnect" event.
 // - Another context calls "extension.connect()" to open a channel to the
 // extension process, or an extension context calls "tabs.connect(tabId)" to
@@ skipping 179 matching lines @@
   int next_port_id_;
 
   // Protects the next_port_id_ variable, since it can be
   // used on the IO thread or the UI thread.
   Lock next_port_id_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionMessageService);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_