Add support code to test the cast system tray item.

ash/ash.gyp

 # Copyright (c) 2012 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,
     # These files lists are shared with the GN build.
     'ash_sources': [
       'accelerators/accelerator_commands.cc',
@@ skipping 723 matching lines @@
       'test/test_suite.cc',
       'test/test_suite.h',
       'test/test_suite_init.h',
       'test/test_suite_init.mm',
       'test/test_system_tray_delegate.cc',
       'test/test_system_tray_delegate.h',
       'test/test_user_wallpaper_delegate.cc',
       'test/test_user_wallpaper_delegate.h',
       'test/test_volume_control_delegate.cc',
       'test/test_volume_control_delegate.h',
+      'test/tray_cast_test_api.cc',
+      'test/tray_cast_test_api.h',
       'test/ui_controls_factory_ash.cc',
       'test/ui_controls_factory_ash.h',
       'test/user_metrics_recorder_test_api.cc',
       'test/user_metrics_recorder_test_api.h',
       'test/virtual_keyboard_test_helper.cc',
       'test/virtual_keyboard_test_helper.h',
     ],
     'ash_shell_lib_sources': [
       '../ui/views/test/test_views_delegate_aura.cc',
       'shell/app_list.cc',
@@ skipping 597 matching lines @@
                   '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
                 ],
               }
             ],
           ],
         },
       ],
     }],
   ],
 }