Use UtilityProcessHost to patch files.

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 757 matching lines @@
         '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/ui/idle_app_name_notification_view_unittest.cc',
         'browser/chromeos/version_loader_unittest.cc',
         'browser/command_updater_unittest.cc',
         'browser/component_updater/test/component_installers_unittest.cc',
-        'browser/component_updater/test/component_patcher_mock.h',
         'browser/component_updater/test/component_patcher_unittest.cc',
         'browser/component_updater/test/component_updater_ping_manager_unittest.cc',
         'browser/component_updater/test/component_updater_service_unittest.cc',
         'browser/component_updater/test/crx_downloader_unittest.cc',
         'browser/component_updater/test/test_installer.cc',
         'browser/component_updater/test/update_checker_unittest.cc',
         'browser/component_updater/test/update_response_unittest.cc',
         'browser/component_updater/test/url_request_post_interceptor.cc',
         'browser/content_settings/content_settings_default_provider_unittest.cc',
         'browser/content_settings/content_settings_mock_observer.cc',
@@ skipping 2117 matching lines @@
             'browser/ui/app_list/test/fake_profile_store.h',
             'browser/ui/app_list/test/fast_show_pickler_unittest.cc',
             'browser/ui/views/app_list/linux/app_list_linux_unittest.cc',
             'browser/ui/views/app_list/win/app_list_win_unittest.cc',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }