Ignore JavaScript messages (alert/confirm/prompt) during unload handlers.

chrome/renderer/render_view.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_RENDERER_RENDER_VIEW_H_
 #define CHROME_RENDERER_RENDER_VIEW_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 764 matching lines @@
                         ThumbnailScore* score);
 
   // Capture a snapshot of a view.  This is used to allow an extension
   // to get a snapshot of a tab using chrome.tabs.captureVisibleTab().
   bool CaptureSnapshot(WebKit::WebView* view, SkBitmap* snapshot);
 
   bool RunJavaScriptMessage(int type,
                             const std::wstring& message,
                             const std::wstring& default_value,
                             const GURL& frame_url,
+                            bool unload_handler_being_run,
                             std::wstring* result);
 
   // Sends a message and runs a nested message loop.
   bool SendAndRunNestedMessageLoop(IPC::SyncMessage* message);
 
   // Adds search provider from the given OpenSearch description URL as a
   // keyword search.
   void AddGURLSearchProvider(const GURL& osd_url,
                              const ViewHostMsg_PageHasOSDD_Type& provider_type);
 
@@ skipping 659 matching lines @@
   // bunch of stuff, you should probably create a helper class and put your
   // data and methods on that to avoid bloating RenderView more.  You can use
   // the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderView);
 };
 
 #endif  // CHROME_RENDERER_RENDER_VIEW_H_