Implement window.alert() and its cousins for extensions....

chrome/chrome.gyp

 # Copyright (c) 2009 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.
 
 {
   'variables': {
     'chromium_code': 1,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
@@ skipping 1721 matching lines @@
         'browser/in_process_webkit/webkit_context.h',
         'browser/in_process_webkit/webkit_thread.cc',
         'browser/in_process_webkit/webkit_thread.h',
         'browser/input_window_dialog.h',
         'browser/input_window_dialog_gtk.cc',
         'browser/input_window_dialog_win.cc',
         'browser/jankometer.cc',
         'browser/jankometer.h',
         'browser/jumplist.cc',
         'browser/jumplist.h',
+        'browser/jsmessage_box_client.h',
         'browser/jsmessage_box_handler.cc',
         'browser/jsmessage_box_handler.h',
         'browser/keychain_mac.cc',
         'browser/keychain_mac.h',
         'browser/language_combobox_model.cc',
         'browser/language_combobox_model.h',
         'browser/language_order_table_model.cc',
         'browser/language_order_table_model.h',
         'browser/load_from_memory_cache_details.h',
         'browser/load_notification_details.h',
@@ skipping 5218 matching lines @@
       ]
     }],
   ],  # 'conditions'
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: