arc: Create sync protos for Arc package.

sync/internal_api/public/base/model_type.h

 // 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.
 
 // Enumerate the various item subtypes that are supported by sync.
 // Each sync object is expected to have an immutable object type.
 // An object's type is inferred from the type of data it holds.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_
 #define SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_
@@ skipping 80 matching lines @@
   APPS,
   // An app setting from the extension settings API.
   APP_SETTINGS,
   // An extension setting from the extension settings API.
   EXTENSION_SETTINGS,
   // App notifications.
   APP_NOTIFICATIONS,  // Deprecated.
   // History delete directives.
   HISTORY_DELETE_DIRECTIVES,
   // Synced push notifications.
-  SYNCED_NOTIFICATIONS,   // Deprecated.
+  SYNCED_NOTIFICATIONS,  // Deprecated.
   // Synced Notification app info.
   SYNCED_NOTIFICATION_APP_INFO,  // Deprecated.
   // Custom spelling dictionary.
   DICTIONARY,
   // Favicon images.
   FAVICON_IMAGES,
   // Favicon tracking information.
   FAVICON_TRACKING,
   // Client-specific metadata, synced before other user types.
   DEVICE_INFO,
@@ skipping 12 matching lines @@
   // Distilled articles.
   ARTICLES,
   // App List items
   APP_LIST,
   // WiFi credentials. Each item contains the information for connecting to one
   // WiFi network. This includes, e.g., network name and password.
   WIFI_CREDENTIALS,
   // Supervised user whitelists. Each item contains a CRX ID (like an extension
   // ID) and a name.
   SUPERVISED_USER_WHITELISTS,
+  // Arc Package items

[pavely, 2016/06/27 18:51:33]

nit: Could you add dot ('.') at the end of comment.

[lgcheng, 2016/06/27 19:54:38]

Done.

+  ARC_PACKAGE,
 
   // ---- Proxy types ----
   // Proxy types are excluded from the sync protocol, but are still considered
   // real user types. By convention, we prefix them with 'PROXY_' to distinguish
   // them from normal protocol types.
 
   // Tab sync. This is a placeholder type, so that Sessions can be implicitly
   // enabled for history sync and tabs sync.
   PROXY_TABS,
   FIRST_PROXY_TYPE = PROXY_TABS,
@@ skipping 211 matching lines @@
 SYNC_EXPORT bool TypeSupportsOrdering(ModelType model_type);
 
 // Returns root_tag for |model_type| in ModelTypeInfo.
 // Difference with ModelTypeToRootTag(), this just simply return toor_tag in
 // ModelTypeInfo.
 SYNC_EXPORT const char* ModelTypeToTag(ModelType model_type);
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_