Add Sync datatype for shared managed user settings.

sync/sync_proto.gypi

 # Copyright 2013 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.
 
 {
   'include_dirs': [
     '..',
   ],
   'defines': [
     'SYNC_IMPLEMENTATION',
@@ skipping 13 matching lines @@
     'protocol/encryption.proto',
     'protocol/experiments_specifics.proto',
     'protocol/extension_setting_specifics.proto',
     'protocol/extension_specifics.proto',
     'protocol/favicon_image_specifics.proto',
     'protocol/favicon_tracking_specifics.proto',
     'protocol/get_updates_caller_info.proto',
     'protocol/history_delete_directive_specifics.proto',
     'protocol/nigori_specifics.proto',
     'protocol/managed_user_setting_specifics.proto',
+    'protocol/managed_user_shared_setting_specifics.proto',
     'protocol/managed_user_specifics.proto',
     'protocol/password_specifics.proto',
     'protocol/preference_specifics.proto',
     'protocol/priority_preference_specifics.proto',
     'protocol/search_engine_specifics.proto',
     'protocol/session_specifics.proto',
     'protocol/sync.proto',
     'protocol/sync_enums.proto',
     'protocol/synced_notification_data.proto',
     'protocol/synced_notification_render.proto',
     'protocol/synced_notification_specifics.proto',
     'protocol/test.proto',
     'protocol/theme_specifics.proto',
     'protocol/typed_url_specifics.proto',
     'protocol/unique_position.proto',
   ],
   'variables': {
     'proto_in_dir': './protocol',
     'proto_out_dir': 'sync/protocol',
     'cc_generator_options': 'dllexport_decl=SYNC_EXPORT:',
     'cc_include': 'sync/base/sync_export.h',
   },
   'includes': [
     '../build/protoc.gypi'
   ],
 }