Enable more tests in GN build.

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',
       'dependencies': [
         '../base/base.gyp:base',
         '../sync/sync.gyp:sync',
         'os_crypt',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
+        # Note: file list duplicated in GN build.
         'sync_driver/backend_data_type_configurer.cc',
         'sync_driver/backend_data_type_configurer.h',
         'sync_driver/change_processor.cc',
         'sync_driver/change_processor.h',
         'sync_driver/data_type_controller.cc',
         'sync_driver/data_type_controller.h',
         'sync_driver/data_type_encryption_handler.cc',
         'sync_driver/data_type_encryption_handler.h',
         'sync_driver/data_type_error_handler.h',
         'sync_driver/data_type_manager.cc',
@@ skipping 64 matching lines @@
         'sync_driver/fake_generic_change_processor.cc',
         'sync_driver/fake_generic_change_processor.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',
       ],
     },
   ],
 }