Remove usage of SequencedWorkerPool::GetNamedSequenceToken from ChromeDownloadManagerDelegate.

chrome/browser/chromeos/drive/download_handler.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_DOWNLOAD_HANDLER_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DOWNLOAD_HANDLER_H_
 
 #include <stdint.h>
 
 #include "base/callback_forward.h"
@@ skipping 53 matching lines @@
   // Gets the target drive path from external data in |download|.
   base::FilePath GetTargetPath(const content::DownloadItem* download);
 
   // Gets the downloaded drive cache file path from external data in |download|.
   base::FilePath GetCacheFilePath(const content::DownloadItem* download);
 
   // Checks if there is a Drive upload associated with |download|
   bool IsDriveDownload(const content::DownloadItem* download);
 
   // Checks a file corresponding to the download item exists in Drive.
-  void CheckForFileExistence(
-      const content::DownloadItem* download,
-      const content::CheckForFileExistenceCallback& callback);
+  void CheckForFileExistence(const content::DownloadItem* download,
+                             content::CheckForFileExistenceCallback callback);
 
   // Calculates request space for |downloads|.
   int64_t CalculateRequestSpace(
       const content::DownloadManager::DownloadVector& downloads);
 
   // Checks available storage space and free disk space if necessary. Actual
   // execution is delayed and rate limited.
   void FreeDiskSpaceIfNeeded();
 
   // Checks available storage space and free disk space if necessary. This is
@@ skipping 50 matching lines @@
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<DownloadHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadHandler);
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DOWNLOAD_HANDLER_H_