Remove the ability of webpages to specify strings for the onbeforeunload dialog.

content/public/browser/javascript_dialog_manager.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_BROWSER_JAVASCRIPT_DIALOG_MANAGER_H_
 #define CONTENT_PUBLIC_BROWSER_JAVASCRIPT_DIALOG_MANAGER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 22 matching lines @@
       const GURL& origin_url,
       const std::string& accept_lang,
       JavaScriptMessageType javascript_message_type,
       const base::string16& message_text,
       const base::string16& default_prompt_text,
       const DialogClosedCallback& callback,
       bool* did_suppress_message) = 0;
 
   // Displays a dialog asking the user if they want to leave a page.
   virtual void RunBeforeUnloadDialog(WebContents* web_contents,
-                                     const base::string16& message_text,
                                      bool is_reload,
                                      const DialogClosedCallback& callback) = 0;
 
   // Accepts or dismisses the active JavaScript dialog, which must be owned
   // by the given |web_contents|. If |prompt_override| is not null, the prompt
   // text of the dialog should be set before accepting. Returns true if the
   // dialog was handled.
   virtual bool HandleJavaScriptDialog(WebContents* web_contents,
                                       bool accept,
                                       const base::string16* prompt_override);
 
   // Cancels all active and pending dialogs for the given WebContents.
   virtual void CancelActiveAndPendingDialogs(WebContents* web_contents) = 0;
 
   // Reset any saved state tied to the given WebContents.
   virtual void ResetDialogState(WebContents* web_contents) = 0;
 
   virtual ~JavaScriptDialogManager() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_JAVASCRIPT_DIALOG_MANAGER_H_