Fix missing string resource for extensions_unittests on Chrome OS

extensions/shell/app_shell.gyp

 # Copyright 2014 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,
   },
   'targets': [
     {
@@ skipping 28 matching lines @@
         '<(DEPTH)/ui/strings/ui_strings.gyp:ui_strings',
       ],
       'actions': [
         {
           'action_name': 'repack_app_shell_pack',
           'variables': {
             'pak_inputs': [
               '<(SHARED_INTERMEDIATE_DIR)/chrome/common_resources.pak',
               '<(SHARED_INTERMEDIATE_DIR)/chrome/extensions_api_resources.pak',
               # TODO(jamescook): Extract the extension/app related resources
-              # from generated_resources_en-US.pak.
+              # from generated_resources_en-US.pak. http://crbug.com/397250
               '<(SHARED_INTERMEDIATE_DIR)/chrome/generated_resources_en-US.pak',
               '<(SHARED_INTERMEDIATE_DIR)/chrome/renderer_resources_100_percent.pak',
               '<(SHARED_INTERMEDIATE_DIR)/content/shell_resources.pak',
               '<(SHARED_INTERMEDIATE_DIR)/extensions/extensions_renderer_resources.pak',
               '<(SHARED_INTERMEDIATE_DIR)/extensions/extensions_resources.pak',
               '<(SHARED_INTERMEDIATE_DIR)/extensions/shell/app_shell_resources.pak',
               '<(SHARED_INTERMEDIATE_DIR)/extensions/strings/extensions_strings_en-US.pak',
               '<(SHARED_INTERMEDIATE_DIR)/ui/resources/ui_resources_100_percent.pak',
               '<(SHARED_INTERMEDIATE_DIR)/ui/strings/app_locale_settings_en-US.pak',
               '<(SHARED_INTERMEDIATE_DIR)/ui/strings/ui_strings_en-US.pak',
@@ skipping 154 matching lines @@
         'browser/shell_browsertest.cc',
         'test/shell_test.h',
         'test/shell_test.cc',
         'test/shell_test_launcher_delegate.cc',
         'test/shell_test_launcher_delegate.h',
         'test/shell_tests_main.cc',
       ],
     },
   ],  # targets
 }