Make FileSystemOperation's lifetime more explicit.

chrome/browser/file_system/browser_file_system_callback_dispatcher.h

-// Copyright (c) 2010 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_FILE_SYSTEM_BROWSER_FILE_SYSTEM_CALLBACK_DISPATCHER_H_
-#define CHROME_BROWSER_FILE_SYSTEM_BROWSER_FILE_SYSTEM_CALLBACK_DISPATCHER_H_
-
-#include "webkit/fileapi/file_system_callback_dispatcher.h"
-
-class FileSystemDispatcherHost;
-
-class BrowserFileSystemCallbackDispatcher
-    : public fileapi::FileSystemCallbackDispatcher {
- public:
-  BrowserFileSystemCallbackDispatcher(FileSystemDispatcherHost* dispatcher_host,
-                                      int request_id);
-  virtual ~BrowserFileSystemCallbackDispatcher();
-
-  // FileSystemCallbackDispatcher implementation.
-  virtual void DidSucceed();
-  virtual void DidReadMetadata(const base::PlatformFileInfo& file_info);
-  virtual void DidReadDirectory(
-      const std::vector<base::FileUtilProxy::Entry>& entries,
-      bool has_more);
-  virtual void DidOpenFileSystem(const std::string& name,
-                                 const FilePath& root_path);
-  virtual void DidFail(base::PlatformFileError error_code);
-  virtual void DidWrite(int64 bytes, bool complete);
-
- private:
-  scoped_refptr<FileSystemDispatcherHost> dispatcher_host_;
-  int request_id_;
-};
-
-#endif  // CHROME_BROWSER_FILE_SYSTEM_BROWSER_FILE_SYSTEM_CALLBACK_DISPATCHER_H_