[SyncFS] Make the snapshot sync of local-to-remote sync parallelization enabled. (2/3)

chrome/browser/sync_file_system/local/local_file_change_tracker.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_LOCAL_LOCAL_FILE_CHANGE_TRACKER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_CHANGE_TRACKER_H_
 
 #include <deque>
 #include <map>
 #include <string>
@@ skipping 13 matching lines @@
 class SequencedTaskRunner;
 }
 
 namespace fileapi {
 class FileSystemContext;
 class FileSystemURL;
 }
 
 namespace leveldb {
 class Env;
+class WriteBatch;
 }
 
 namespace sync_file_system {
 
 // Tracks local file changes for cloud-backed file systems.
 // All methods must be called on the file_task_runner given to the constructor.
 // Owned by FileSystemContext.
 class LocalFileChangeTracker
     : public fileapi::FileUpdateObserver,
       public fileapi::FileChangeObserver {
@@ skipping 113 matching lines @@
       fileapi::FileSystemContext* file_system_context);
   void RecordChange(const fileapi::FileSystemURL& url,
                     const FileChange& change);
 
   static void RecordChangeToChangeMaps(const fileapi::FileSystemURL& url,
                                        const FileChange& change,
                                        int change_seq,
                                        FileChangeMap* changes,
                                        ChangeSeqMap* change_seqs);
 
+  void ResetForURL(const fileapi::FileSystemURL& url,
+                   int change_seq,
+                   leveldb::WriteBatch* batch);
+
   bool initialized_;
 
   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 
   FileChangeMap changes_;
   ChangeSeqMap change_seqs_;
 
   FileChangeMap mirror_changes_;  // For mirrors.
   FileChangeMap demoted_changes_;  // For demoted changes.
 
   scoped_ptr<TrackerDB> tracker_db_;
 
   // Change sequence number. Briefly gives a hint about the order of changes,
   // but they are updated when a new change comes on the same file (as
   // well as Drive's changestamps).
   int64 current_change_seq_;
 
   // This can be accessed on any threads (with num_changes_lock_).
   int64 num_changes_;
   mutable base::Lock num_changes_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalFileChangeTracker);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_CHANGE_TRACKER_H_