A11y: Add a browser test of TrayAccessibility.

chrome/chrome_tests.gypi

 # 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' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
       'common/pref_names.cc',
@@ skipping 881 matching lines @@
         'browser/chromeos/login/screen_locker_tester.cc',
         'browser/chromeos/login/screen_locker_tester.h',
         'browser/chromeos/login/update_screen_browsertest.cc',
         'browser/chromeos/login/user_image_manager_browsertest.cc',
         'browser/chromeos/login/wizard_controller_browsertest.cc',
         'browser/chromeos/login/wizard_in_process_browser_test.cc',
         'browser/chromeos/login/wizard_in_process_browser_test.h',
         'browser/chromeos/media/media_player_browsertest.cc',
         'browser/chromeos/memory/oom_priority_manager_browsertest.cc',
         'browser/chromeos/process_proxy/process_proxy_browsertest.cc',
+        'browser/chromeos/system/tray_accessibility_browsertest.cc',
         'browser/chromeos/ui/idle_logout_dialog_view_browsertest.cc',
         'browser/collected_cookies_browsertest.cc',
         'browser/content_settings/content_settings_browsertest.cc',
         'browser/crash_recovery_browsertest.cc',
         'browser/custom_handlers/protocol_handler_registry_browsertest.cc',
         'browser/debugger/devtools_sanity_browsertest.cc',
         'browser/do_not_track_browsertest.cc',
         'browser/download/download_browsertest.cc',
         'browser/download/download_danger_prompt_browsertest.cc',
         'browser/download/download_query_unittest.cc',
@@ skipping 1903 matching lines @@
             'sync_integration_tests.isolate',
           ],
           'sources': [
             'sync_integration_tests.isolate',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }