Correct forward declaration.

chrome/test/automation/tab_proxy.h

 // Copyright (c) 2006-2008 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_TEST_AUTOMATION_TAB_PROXY_H_
 #define CHROME_TEST_AUTOMATION_TAB_PROXY_H_
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <wtypes.h>
 #endif
 
 #include <string>
 #include <vector>
 
 #include "base/observer_list.h"
 #include "chrome/browser/download/save_package.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/security_style.h"
 #include "chrome/test/automation/automation_constants.h"
 #include "chrome/test/automation/automation_handle_tracker.h"
 
 class ConstrainedWindowProxy;
 class GURL;
 class Value;
-class IPC::Message;
+namespace IPC {
+class Message;
+};
 
 enum FindInPageDirection { BACK = 0, FWD = 1 };
 enum FindInPageCase { IGNORE_CASE = 0, CASE_SENSITIVE = 1 };
 
 class TabProxy : public AutomationResourceProxy {
  public:
   class TabProxyDelegate {
    public:
     virtual void OnMessageReceived(TabProxy* tab, const IPC::Message& msg) {}
   };
@@ skipping 269 matching lines @@
   void OnMessageReceived(const IPC::Message& message);
  protected:
   virtual ~TabProxy() {}
  private:
   Lock list_lock_;  // Protects the observers_list_.
   ObserverList<TabProxyDelegate> observers_list_;
   DISALLOW_COPY_AND_ASSIGN(TabProxy);
 };
 
 #endif  // CHROME_TEST_AUTOMATION_TAB_PROXY_H_