Use delete journal to remove bookmarks that are already deleted in sync model

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/internal_api/public/base/model_type.h"
+#include "sync/protocol/sync.pb.h"
+
+namespace syncer {
+
+class BaseTransaction;
+
+struct BookmarkDeleteJournal {
+  int64 id;

[tim (not reviewing), 2013/01/14 23:32:48]

What is this id? (Metahandle? syncable::Id? BookmarkNode id?)

[haitaol1, 2013/01/15 19:44:31]

It's metahandle of delete journal entry. Added comments.

On 2013/01/14 23:32:48, timsteele wrote:

+  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 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_