Enable chrome.mdns for Chrome Apps

chrome/chrome_tests_unit.gypi

 # Copyright 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': {
     'chrome_unit_tests_sources': [
       '../apps/saved_files_service_unittest.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.h',
       '../components/autofill/content/renderer/test_password_generation_agent.cc',
@@ skipping 325 matching lines @@
       'browser/extensions/api/image_writer_private/operation_unittest.cc',
       'browser/extensions/api/image_writer_private/removable_storage_provider_chromeos_unittest.cc',
       'browser/extensions/api/image_writer_private/test_utils.cc',
       'browser/extensions/api/image_writer_private/write_from_file_operation_unittest.cc',
       'browser/extensions/api/image_writer_private/write_from_url_operation_unittest.cc',
       'browser/extensions/api/log_private/syslog_parser_unittest.cc',
       'browser/extensions/api/mdns/dns_sd_registry_unittest.cc',
       'browser/extensions/api/messaging/native_message_process_host_unittest.cc',
       'browser/extensions/api/messaging/native_messaging_host_manifest_unittest.cc',
       'browser/extensions/api/messaging/native_messaging_policy_handler_unittest.cc',
+      'browser/extensions/api/mdns/mdns_api_unittest.cc',
       'browser/extensions/api/omnibox/omnibox_unittest.cc',
       'browser/extensions/api/permissions/permissions_api_helpers_unittest.cc',
       'browser/extensions/api/preference/preference_api_prefs_unittest.cc',
       'browser/extensions/api/proxy/proxy_api_helpers_unittest.cc',
       'browser/extensions/api/push_messaging/obfuscated_gaia_id_fetcher_unittest.cc',
       'browser/extensions/api/push_messaging/push_messaging_invalidation_handler_unittest.cc',
       'browser/extensions/api/signed_in_devices/id_mapping_helper_unittest.cc',
       'browser/extensions/api/signed_in_devices/signed_in_devices_api_unittest.cc',
       'browser/extensions/api/signed_in_devices/signed_in_devices_manager_unittest.cc',
       'browser/extensions/api/socket/socket_api_unittest.cc',
@@ skipping 2509 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }