Cleanup: Remove more forward declarations in various chrome/browser directories.

chrome/browser/debugger/inspectable_tab_proxy.h

 // Copyright (c) 2011 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_DEBUGGER_INSPECTABLE_TAB_PROXY_H_
 #define CHROME_BROWSER_DEBUGGER_INSPECTABLE_TAB_PROXY_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "content/browser/debugger/devtools_client_host.h"
 
 class DebuggerRemoteService;
 class DevToolsClientHost;
 class DevToolsClientHostImpl;
-struct DevToolsMessageData;
 class TabContentsWrapper;
 
 // Proxies debugged tabs' TabContentsWrapper using their UIDs.
 // Keeps track of tabs being debugged so that we can detach from
 // them on remote debugger connection loss.
 class InspectableTabProxy {
  public:
   typedef base::hash_map<int32, TabContentsWrapper*> TabMap;
   typedef base::hash_map<int32, DevToolsClientHostImpl*> IdToClientHostMap;
 
@@ skipping 53 matching lines @@
   void OnDebuggerOutput(const std::string& msg);
   virtual void FrameNavigating(const std::string& url);
   void TabClosed();
 
   int32 id_;
   DebuggerRemoteService* service_;
   InspectableTabProxy::IdToClientHostMap* map_;
 };
 
 #endif  // CHROME_BROWSER_DEBUGGER_INSPECTABLE_TAB_PROXY_H_