[SyncFS] Migrate ServiceMetadata from MDDB to MDDBIndex.

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/bind.h"
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/sync_file_system/drive_backend/metadata_database.pb.h"
 #include "chrome/browser/sync_file_system/sync_status_code.h"
 #include "google_apis/drive/gdata_errorcode.h"
 #include "webkit/common/blob/scoped_file.h"
 
 namespace google_apis {
 class ChangeResource;
 class FileResource;
 class ResourceEntry;
 }
 
 namespace leveldb {
+class DB;
 class WriteBatch;
 }
 
 namespace sync_file_system {
 namespace drive_backend {
 
 void PutServiceMetadataToBatch(const ServiceMetadata& service_metadata,
                                leveldb::WriteBatch* batch);
 void PutFileMetadataToBatch(const FileMetadata& file,
                             leveldb::WriteBatch* batch);
@@ skipping 12 matching lines @@
 std::string GetTrackerTitle(const FileTracker& tracker);
 
 SyncStatusCode GDataErrorCodeToSyncStatusCode(
     google_apis::GDataErrorCode error);
 
 // Returns true if |str| starts with |prefix|, and removes |prefix| from |str|.
 // If |out| is not NULL, the result is stored in it.
 bool RemovePrefix(const std::string& str, const std::string& prefix,
                   std::string* out);
 
+scoped_ptr<ServiceMetadata> ReadServiceMetadata(leveldb::DB* db);
+scoped_ptr<ServiceMetadata> InitializeServiceMetadata(
+    leveldb::DB* db, leveldb::WriteBatch* batch);
+
 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) {
@@ skipping 13 matching lines @@
 base::Callback<R()> CreateComposedFunction(
     const base::Callback<T()>& g,
     const base::Callback<R(S)>& f) {
   return base::Bind(&ComposeFunction<R, S, T>, g, f);
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_DRIVE_BACKEND_UTIL_H_