(For-try) Divide recursive Copy/Move into multiple async tasks

webkit/fileapi/isolated_file_util.h

 // Copyright (c) 2012 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 WEBKIT_FILEAPI_ISOLATED_FILE_UTIL_H_
 #define WEBKIT_FILEAPI_ISOLATED_FILE_UTIL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "webkit/fileapi/local_file_util.h"
 #include "webkit/storage/webkit_storage_export.h"
@@ skipping 25 matching lines @@
   // FileSystemFileUtil overrides.
   virtual base::PlatformFileError GetFileInfo(
       FileSystemOperationContext* context,
       const FileSystemURL& url,
       base::PlatformFileInfo* file_info,
       FilePath* platform_path) OVERRIDE;
   virtual scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
       FileSystemOperationContext* context,
       const FileSystemURL& root_url,
       bool recursive) OVERRIDE;
-  virtual bool IsDirectoryEmpty(
-      FileSystemOperationContext* context,
-      const FileSystemURL& url) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DraggedFileUtil);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_ISOLATED_FILE_UTIL_H_