Add policies to control power management on the Chrome OS login screen

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 668 matching lines @@
         'browser/chromeos/policy/configuration_policy_handler_chromeos_unittest.cc',
         'browser/chromeos/policy/device_cloud_policy_manager_chromeos_unittest.cc',
         'browser/chromeos/policy/device_cloud_policy_store_chromeos_unittest.cc',
         'browser/chromeos/policy/device_local_account_policy_service_unittest.cc',
         'browser/chromeos/policy/enterprise_install_attributes_unittest.cc',
         'browser/chromeos/policy/network_configuration_updater_impl_cros_unittest.cc',
         '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/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_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',
@@ skipping 1936 matching lines @@
               # more details.
               'DebugInformationFormat': '3',
               'ProgramDataBaseFileName': '<(PRODUCT_DIR)/unit_tests.exe.pdb',
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }