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

chrome/common/render_messages_internal.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.
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "build/build_config.h"
@@ skipping 1316 matching lines @@
 // Initiates a download based on user actions like 'ALT+click'.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_DownloadUrl,
                     GURL /* url */,
                     GURL /* referrer */)
 
 // Used to go to the session history entry at the given offset (ie, -1 will
 // return the "back" item).
 IPC_MESSAGE_ROUTED1(ViewHostMsg_GoToEntryAtOffset,
                     int /* offset (from current) of history item to get */)
 
-IPC_SYNC_MESSAGE_ROUTED4_2(ViewHostMsg_RunJavaScriptMessage,
+IPC_SYNC_MESSAGE_ROUTED5_2(ViewHostMsg_RunJavaScriptMessage,
                            std::wstring /* in - alert message */,
                            std::wstring /* in - default prompt */,
                            GURL         /* in - originating page URL */,
                            int          /* in - dialog flags */,
+                           bool         /* in - unload handler being run? */,
                            bool         /* out - success */,
                            std::wstring /* out - prompt field */)
 
 // Provides the contents for the given page that was loaded recently.
 IPC_MESSAGE_ROUTED5(ViewHostMsg_PageContents,
                     GURL         /* URL of the page */,
                     int32        /* page id */,
                     string16     /* page contents */,
                     std::string  /* page ISO639_1 language code */,
                     bool         /* whether the page can be translated */)
@@ skipping 951 matching lines @@
 // while performing stress testing.
 IPC_MESSAGE_ROUTED2(ViewMsg_JavaScriptStressTestControl,
                     int /* cmd */,
                     int /* param */)
 
 // Register a new handler for URL requests with the given scheme.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_RegisterProtocolHandler,
                     std::string /* scheme */,
                     GURL /* url */,
                     string16 /* title */)