Add missing dependency of sync_driver on policy_component.

components/sync_driver.gypi

 # Copyright 2014 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': [
     {
       # GN version: //components/sync_driver
       'target_name': 'sync_driver',
       'type': 'static_library',
@@ skipping 139 matching lines @@
             'sessions_content',
           ],
         }, {  # OS==ios
           'dependencies': [
             'sessions_ios',
           ],
         }],
         ['configuration_policy==1', {
           'dependencies': [
             'policy',
+            'policy_component',
           ],
           'sources': [
             'sync_driver/sync_policy_handler.cc',
             'sync_driver/sync_policy_handler.h',
           ],
         }],
       ],
     },
     {
       'target_name': 'sync_driver_test_support',
@@ skipping 31 matching lines @@
         'sync_driver/local_device_info_provider_mock.cc',
         'sync_driver/local_device_info_provider_mock.h',
         'sync_driver/model_associator_mock.cc',
         'sync_driver/model_associator_mock.h',
         'sync_driver/non_ui_data_type_controller_mock.cc',
         'sync_driver/non_ui_data_type_controller_mock.h',
       ],
     },
   ],
 }