chromeos: power: Refactor RendererFreezer and add tests

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/app_shim/app_shim_host_mac_unittest.cc',
       '../apps/app_shim/extension_app_shim_handler_mac_unittest.cc',
       '../apps/saved_files_service_unittest.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
@@ skipping 217 matching lines @@
       '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_unittest.cc',
       'browser/chromeos/policy/recommendation_restorer_unittest.cc',
       'browser/chromeos/policy/server_backed_state_keys_broker_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_data_collector_unittest.cc',
       'browser/chromeos/power/power_prefs_unittest.cc',
+      'browser/chromeos/power/renderer_freezer_unittest.cc',
       'browser/chromeos/preferences_unittest.cc',
       'browser/chromeos/profiles/profile_list_chromeos_unittest.cc',
       'browser/chromeos/proxy_config_service_impl_unittest.cc',
       'browser/chromeos/session_length_limiter_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/session_manager_operation_unittest.cc',
       'browser/chromeos/settings/stub_cros_settings_provider_unittest.cc',
@@ skipping 2623 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }