Add some browser tests for the cast system tray.

chrome/chrome_tests.gypi

 # Copyright 2013 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': {
     'chrome_browser_extensions_test_support_sources': [
       # A list of sources which is shared between different browser tests.
       'browser/apps/app_browsertest_util.cc',
       'browser/apps/app_browsertest_util.h',
       'browser/extensions/browsertest_util.cc',
@@ skipping 412 matching lines @@
       'browser/translate/translate_manager_browsertest.cc',
       'browser/ui/ash/accelerator_commands_browsertest.cc',
       'browser/ui/ash/accelerator_controller_browsertest.cc',
       'browser/ui/ash/keyboard_controller_browsertest.cc',
       'browser/ui/ash/launcher/chrome_launcher_controller_browsertest.cc',
       'browser/ui/ash/launcher/launcher_favicon_loader_browsertest.cc',
       'browser/ui/ash/multi_user/multi_user_window_manager_test.cc',
       'browser/ui/ash/multi_user/multi_user_window_manager_test.h',
       'browser/ui/ash/shelf_browsertest.cc',
       'browser/ui/ash/system_tray_delegate_chromeos_browsertest_chromeos.cc',
+      'browser/ui/ash/system_tray_tray_cast_browsertest_chromeos.cc',
       'browser/ui/ash/volume_controller_browsertest_chromeos.cc',
       'browser/ui/autofill/autofill_dialog_controller_browsertest.cc',
       'browser/ui/autofill/autofill_dialog_view_tester.h',
       'browser/ui/autofill/card_unmask_prompt_view_browsertest.cc',
       'browser/ui/autofill/card_unmask_prompt_view_tester.h',
       'browser/ui/autofill/mock_address_validator.cc',
       'browser/ui/autofill/mock_address_validator.h',
       'browser/ui/autofill/password_generation_popup_view_browsertest.cc',
       'browser/ui/autofill/password_generation_popup_view_tester.h',
       'browser/ui/autofill/test_generated_credit_card_bubble_controller.cc',
@@ skipping 2895 matching lines @@
             'utility',
           ],
           'sources': [
             'tools/service_discovery_sniffer/service_discovery_sniffer.cc',
             'tools/service_discovery_sniffer/service_discovery_sniffer.h',
           ],
         }]
     }],
   ],  # 'conditions'
 }