settings: Add async system salt retrieval logic in DeviceOAuth2TokenServiceFactory

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.
 {
   'targets': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 699 matching lines @@
         'browser/chromeos/policy/proxy_policy_provider_unittest.cc',
         'browser/chromeos/policy/recommendation_restorer_unittest.cc',
         'browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc',
         'browser/chromeos/policy/user_cloud_policy_store_chromeos_unittest.cc',
         'browser/chromeos/power/power_prefs_unittest.cc',
         'browser/chromeos/preferences_unittest.cc',
         'browser/chromeos/profiles/profile_list_chromeos_unittest.cc',
         'browser/chromeos/session_length_limiter_unittest.cc',
         'browser/chromeos/proxy_config_service_impl_unittest.cc',
         'browser/chromeos/settings/cros_settings_unittest.cc',
+        'browser/chromeos/settings/device_oauth2_token_service_factory_unittest.cc',
         'browser/chromeos/settings/device_oauth2_token_service_unittest.cc',
         'browser/chromeos/settings/device_settings_provider_unittest.cc',
         'browser/chromeos/settings/device_settings_service_unittest.cc',
         'browser/chromeos/settings/owner_key_util_unittest.cc',
         'browser/chromeos/settings/session_manager_operation_unittest.cc',
         'browser/chromeos/settings/stub_cros_settings_provider_unittest.cc',
         'browser/chromeos/system/automatic_reboot_manager_unittest.cc',
         'browser/chromeos/version_loader_unittest.cc',
         'browser/command_updater_unittest.cc',
         'browser/component_updater/test/component_installers_unittest.cc',
@@ skipping 2143 matching lines @@
             'browser/ui/app_list/test/fake_profile.h',
             'browser/ui/app_list/test/fake_profile_store.cc',
             'browser/ui/app_list/test/fake_profile_store.h',
             'browser/ui/app_list/test/fast_show_pickler_unittest.cc',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }