[SyncFS] Refactor MetadataDatabase on dirty flag handling and sync-root creation

chrome/browser/sync_file_system/drive_backend/metadata_database.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_METADATA_DATABASE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 384 matching lines @@
 
   void RemoveTracker(int64 tracker_id, leveldb::WriteBatch* batch);
   void RemoveTrackerIgnoringSameTitle(int64 tracker_id,
                                       leveldb::WriteBatch* batch);
   void RemoveTrackerInternal(int64 tracker_id,
                              leveldb::WriteBatch* batch,
                              bool ignoring_same_title);
   void MaybeAddTrackersForNewFile(const FileMetadata& file,
                                   leveldb::WriteBatch* batch);
 
-  void MarkSingleTrackerDirty(FileTracker* tracker,
-                              leveldb::WriteBatch* batch);
+  void MarkSingleTrackerAsDirty(FileTracker* tracker,
+                                leveldb::WriteBatch* batch);
+  void ClearDirty(FileTracker* tracker, leveldb::WriteBatch* batch);
   void MarkTrackerSetDirty(TrackerSet* trackers,
                            leveldb::WriteBatch* batch);
   void MarkTrackersDirtyByFileID(const std::string& file_id,
                                  leveldb::WriteBatch* batch);
   void MarkTrackersDirtyByPath(int64 parent_tracker_id,
                                const std::string& title,
                                leveldb::WriteBatch* batch);
 
   void EraseTrackerFromFileIDIndex(FileTracker* tracker,
                                    leveldb::WriteBatch* batch);
@@ skipping 65 matching lines @@
 
   base::WeakPtrFactory<MetadataDatabase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MetadataDatabase);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_