[Sync] Move //sync to //components/sync.

components/sync/protocol/article_specifics.proto

 // 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.
 //
 // Sync protocol datatype extension for the article.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 option retain_unknown_fields = true;
@@ skipping 13 matching lines @@
   optional ArticleAttachments attachments = 4;
 }
 
 message ArticlePage {
   optional string url = 1;
 }
 
 message ArticleAttachments {
   optional AttachmentIdProto distilled_article = 1;
 }