chromeos: Destruct DriveResourceMetadata on the blocking pool

chrome/browser/chromeos/drive/drive_file_system.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 CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_H_
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/timer.h"
 #include "chrome/browser/chromeos/drive/change_list_loader.h"
 #include "chrome/browser/chromeos/drive/change_list_loader_observer.h"
 #include "chrome/browser/chromeos/drive/drive_file_system_interface.h"
+#include "chrome/browser/chromeos/drive/drive_file_system_util.h"
 #include "chrome/browser/chromeos/drive/file_system/drive_operations.h"
 #include "chrome/browser/chromeos/drive/file_system/operation_observer.h"
 #include "chrome/browser/google_apis/gdata_errorcode.h"
 
 class PrefChangeRegistrar;
 class Profile;
 
 namespace base {
 struct PlatformFileInfo;
 class SequencedTaskRunner;
@@ skipping 424 matching lines @@
       scoped_ptr<DriveEntryProto> entry_proto,
       const GetEntryInfoCallback& callback,
       DriveFileError error,
       const base::FilePath& local_cache_path);
   void CheckLocalModificationAndRunAfterGetFileInfo(
       scoped_ptr<DriveEntryProto> entry_proto,
       const GetEntryInfoCallback& callback,
       base::PlatformFileInfo* file_info,
       bool get_file_info_result);
 
-  scoped_ptr<DriveResourceMetadata> resource_metadata_;
+  util::DestroyHelper<DriveResourceMetadata>::scoped_ptr resource_metadata_;
 
   // The profile hosts the DriveFileSystem via DriveSystemService.
   Profile* profile_;
 
   // The cache owned by DriveSystemService.
   DriveCache* cache_;
 
   // The uploader owned by DriveSystemService.
   google_apis::DriveUploaderInterface* uploader_;
 
@@ skipping 40 matching lines @@
   // Note: These should remain the last member so they'll be destroyed and
   // invalidate the weak pointers before any other members are destroyed.
   base::WeakPtrFactory<DriveFileSystem> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DriveFileSystem);
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_H_