Use external ID to match native model nodes during bookmark association.

sync/internal_api/public/delete_journal.h

 // 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.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_DELETE_JOURNAL_H_
 #define SYNC_INTERNAL_API_PUBLIC_DELETE_JOURNAL_H_
 
 #include <vector>
 
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 
 class BaseTransaction;
 
 struct BookmarkDeleteJournal {
   int64 id;   // Metahandle of delete journal entry.
+  int64 external_id;  // Bookmark ID in the native model.
   bool is_folder;
   sync_pb::EntitySpecifics specifics;
 };
 typedef std::vector<BookmarkDeleteJournal> BookmarkDeleteJournalList;
 
 // Static APIs for passing delete journals between syncer::syncable namspace
 // and syncer namespace.
 class SYNC_EXPORT DeleteJournal {
  public:
   // Return info about deleted bookmark entries stored in the delete journal
   // of |trans|'s directory.
   // TODO(haitaol): remove this after SyncData supports bookmarks and
   //                all types of delete journals can be returned as
   //                SyncDataList.
   static void GetBookmarkDeleteJournals(
       BaseTransaction* trans, BookmarkDeleteJournalList *delete_journals);
 
   // Purge delete journals of given IDs from |trans|'s directory.
   static void PurgeDeleteJournals(BaseTransaction* trans,
                                   const std::set<int64>& ids);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_DELETE_JOURNAL_H_