Check node references during sync DB init

chrome/browser/sync/syncable/dir_open_result.h

 // Copyright (c) 2009 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 CHROME_BROWSER_SYNC_SYNCABLE_DIR_OPEN_RESULT_H_
 #define CHROME_BROWSER_SYNC_SYNCABLE_DIR_OPEN_RESULT_H_
 #pragma once
 
 namespace syncable {
 enum DirOpenResult { OPENED,   // success.
                      FAILED_NEWER_VERSION,  // DB version is too new.
                      FAILED_MAKE_REPOSITORY,  // Couldn't create subdir.
                      FAILED_OPEN_DATABASE,  // sqlite_open() failed.
                      FAILED_DISK_FULL,  // The disk is full.
                      FAILED_DATABASE_CORRUPT,  // Something is wrong with the DB
+                     FAILED_LOGICAL_CORRUPTION, // Invalid database contents
 };
 }  // namespace syncable
 
 #endif  // CHROME_BROWSER_SYNC_SYNCABLE_DIR_OPEN_RESULT_H_