Reapply r50859 with chromeos fixes.

app/app_base.gypi

 # Copyright (c) 2010 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.
 
 {
   'target_defaults': {
     'variables': {
       'app_base_target': 0,
     },
     'target_conditions': [
@@ skipping 141 matching lines @@
         'l10n_util_mac.h',
         'l10n_util_mac.mm',
         'l10n_util_posix.cc',
         'l10n_util_win.cc',
         'l10n_util_win.h',
         'linear_animation.cc',
         'linear_animation.h',
         'menus/accelerator.h',
         'menus/accelerator_gtk.h',
         'menus/accelerator_cocoa.h',
+        'menus/button_menu_item_model.cc',
+        'menus/button_menu_item_model.h',
         'menus/menu_model.cc',
         'menus/menu_model.h',
         'menus/simple_menu_model.cc',
         'menus/simple_menu_model.h',
         'message_box_flags.h',
         'multi_animation.cc',
         'multi_animation.h',
         'os_exchange_data_provider_gtk.cc',
         'os_exchange_data_provider_gtk.h',
         'os_exchange_data_provider_win.cc',
@@ skipping 220 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }