Reduce the memory usage of bookmarks storage

components/bookmarks/browser/bookmark_client.cc

 // 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.
 
 #include "components/bookmarks/browser/bookmark_client.h"
 
 #include "base/logging.h"
 
 namespace bookmarks {
 
@@ skipping 13 matching lines @@
 
 bool BookmarkClient::SupportsTypedCountForUrls() {
   return false;
 }
 
 void BookmarkClient::GetTypedCountForUrls(
     UrlTypedCountMap* url_typed_count_map) {
   NOTREACHED();
 }
 
+std::vector<std::string> BookmarkClient::ExecludedMetaKeys() {
+  return std::vector<std::string>();
+}
+
 }  // namespace bookmarks