arc: Create sync protos for Arc package.

components/sync_driver/user_selectable_sync_type.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_USER_SELECTABLE_SYNC_TYPE_H_
 #define COMPONENTS_SYNC_DRIVER_USER_SELECTABLE_SYNC_TYPE_H_
 
 namespace sync_driver {
 namespace user_selectable_type {
 
@@ skipping 20 matching lines @@
   EXTENSIONS = 6,
   PROXY_TABS = 7,
   APPS = 8,
   // TODO(petewil): There was talk of removing this from user selectable sync
   // types.  Should we?
   SYNCED_NOTIFICATIONS = 9,
   WIFI_CREDENTIAL = 10,
 
   // The datatypes below are implicitly synced, and are not exposed via user
   // selectable checkboxes.
+  // TODO(lgcheng) ARC_PACKAGE would be selectable.
 
   // AUTOFILL_PROFILE,
   // NIGORI,
   // DICTIONARY
   // SEARCH_ENGINES,
   // APP_LIST,
   // APP_SETTINGS,
   // EXTENSION_SETTINGS,
   // APP_NOTIFICATIONS,
   // DEVICE_INFO,
   // EXPERIMENTS,
   // PRIORITY_PREFERENCES,
   // SESSIONS,
   // HISTORY_DELETE_DIRECTIVES,
   // FAVICON_IMAGES,
   // FAVICON_TRACKING,
   // ARTICLE,
-  // SYNCED_NOTIFICATION_APP_INFO
+  // SYNCED_NOTIFICATION_APP_INFO,
+  // ARC_PACKAGE
 
   // Number of sync datatypes exposed to the user via checboxes in the UI.
   SELECTABLE_DATATYPE_COUNT = 11,
 };
 
 }  // namespace user_selectable_type
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_USER_SELECTABLE_SYNC_TYPE_H_