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

sync/protocol/bookmark_specifics.proto

-// Copyright (c) 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.
-//
-// Sync protocol datatype extension for bookmarks.
-
-// Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
-// any fields in this file.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-option retain_unknown_fields = true;
-
-package sync_pb;
-
-// Corresponds to a single meta info key/value pair for a bookmark node.
-message MetaInfo {
-  optional string key = 1;
-  optional string value = 2;
-}
-
-// Properties of bookmark sync objects.
-message BookmarkSpecifics {
-  optional string url = 1;
-  optional bytes favicon = 2;
-  optional string title = 3;
-  // Corresponds to BookmarkNode::date_added() and is the internal value from
-  // base::Time.
-  optional int64 creation_time_us = 4;
-  optional string icon_url = 5;
-  repeated MetaInfo meta_info = 6;
-}
-