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

content/browser/web_contents/web_contents_impl.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_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <stdint.h>
 
 #include <functional>
@@ skipping 400 matching lines @@
   void SwappedOut(RenderFrameHost* render_frame_host) override;
   void ShowContextMenu(RenderFrameHost* render_frame_host,
                        const ContextMenuParams& params) override;
   void RunJavaScriptMessage(RenderFrameHost* render_frame_host,
                             const base::string16& message,
                             const base::string16& default_prompt,
                             const GURL& frame_url,
                             JavaScriptMessageType type,
                             IPC::Message* reply_msg) override;
   void RunBeforeUnloadConfirm(RenderFrameHost* render_frame_host,
-                              const base::string16& message,
                               bool is_reload,
                               IPC::Message* reply_msg) override;
   void DidAccessInitialDocument() override;
   void DidChangeName(RenderFrameHost* render_frame_host,
                      const std::string& name) override;
   void DocumentOnLoadCompleted(RenderFrameHost* render_frame_host) override;
   void UpdateStateForFrame(RenderFrameHost* render_frame_host,
                            const PageState& page_state) override;
   void UpdateTitle(RenderFrameHost* render_frame_host,
                    int32_t page_id,
@@ skipping 924 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_