athena: Use overlay scrollbars.

athena/main/athena_main.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 14 matching lines @@
         # search_engines and its dependencies. See crbug.com/386171
         # TODO(mukai): declare those symbols for Athena.
         '../../components/components.gyp:infobars_test_support',
         '../../components/components.gyp:search_engines',
         '../../extensions/shell/app_shell.gyp:app_shell_lib',
         '../../skia/skia.gyp:skia',
         '../../ui/accessibility/accessibility.gyp:ax_gen',
         '../../ui/app_list/app_list.gyp:app_list',
         '../../ui/chromeos/ui_chromeos.gyp:ui_chromeos',
         '../../ui/keyboard/keyboard.gyp:keyboard',
+        '../../ui/native_theme/native_theme.gyp:native_theme',
         '../../ui/views/views.gyp:views',
         '../../url/url.gyp:url_lib',
       ],
       'include_dirs': [
         '../..',
       ],
       'sources': [
         'athena_app_window_controller.cc',
         'athena_app_window_controller.h',
         'athena_launcher.cc',
@@ skipping 23 matching lines @@
         '../athena.gyp:athena_lib',
         '../athena.gyp:athena_test_support',
         '../resources/athena_resources.gyp:athena_pak',
       ],
       'sources': [
         'athena_shell.cc',
       ],
     }
   ],  # targets
 }