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

chrome/browser/extensions/extension_devtools_bridge.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// 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_DEVTOOLS_BRIDGE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_DEVTOOLS_BRIDGE_H_
 #pragma once
 
 #include <string>
 
 #include "base/ref_counted.h"
 #include "chrome/browser/debugger/devtools_client_host.h"
 #include "chrome/browser/extensions/extension_devtools_manager.h"
 #include "chrome/browser/extensions/extension_message_service.h"
 
 class Profile;
-struct DevToolsMessageData;
 
 // This class is a DevToolsClientHost that fires extension events.
 class ExtensionDevToolsBridge : public DevToolsClientHost {
  public:
   ExtensionDevToolsBridge(int tab_id, Profile* profile);
   virtual ~ExtensionDevToolsBridge();
 
   bool RegisterAsDevToolsClientHost();
   void UnregisterAsDevToolsClientHost();
 
@@ skipping 19 matching lines @@
   // The names of the events fired at extensions depend on the tab id,
   // so we store the various event names in each bridge.
   const std::string on_page_event_name_;
   const std::string on_tab_close_event_name_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionDevToolsBridge);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_DEVTOOLS_BRIDGE_H_