[SyncFS] Wire up MetadataDatabaseIndex to MetadataDatabase

chrome/browser/sync_file_system/drive_backend/drive_backend_util.h

 // Copyright 2013 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_FILE_SYSTEM_DRIVE_BACKEND_DRIVE_BACKEND_UTIL_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_DRIVE_BACKEND_UTIL_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 50 matching lines @@
 bool HasFileAsParent(const FileDetails& details, const std::string& file_id);
 
 std::string GetMimeTypeFromTitle(const base::FilePath& title);
 
 scoped_ptr<google_apis::ResourceEntry> GetOldestCreatedFolderResource(
     ScopedVector<google_apis::ResourceEntry> list);
 
 SyncStatusCode GDataErrorCodeToSyncStatusCode(
     google_apis::GDataErrorCode error);
 
+template <typename T>
+scoped_ptr<T> Clone(const T* obj) {
+  if (!obj)
+    return scoped_ptr<T>();
+  return scoped_ptr<T>(new T(*obj));
+}
+
 template <typename Src, typename Dest>
 void AppendContents(const Src& src, Dest* dest) {
   dest->insert(dest->end(), src.begin(), src.end());
 }
 
 template <typename Container>
 const typename Container::mapped_type& LookUpMap(
     const Container& container,
     const typename Container::key_type& key,
     const typename Container::mapped_type& default_value) {
   typename Container::const_iterator found = container.find(key);
   if (found == container.end())
     return default_value;
   return found->second;
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_DRIVE_BACKEND_UTIL_H_