Remove usage of SequencedWorkerPool::GetNamedSequenceToken from ChromeDownloadManagerDelegate.

content/public/browser/download_manager_delegate.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 CONTENT_PUBLIC_BROWSER_DOWNLOAD_MANAGER_DELEGATE_H_
 #define CONTENT_PUBLIC_BROWSER_DOWNLOAD_MANAGER_DELEGATE_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
@@ skipping 46 matching lines @@
     base::Callback<void(const base::FilePath& target_path,
                         DownloadItem::TargetDisposition disposition,
                         DownloadDangerType danger_type,
                         const base::FilePath& intermediate_path,
                         DownloadInterruptReason interrupt_reason)>;
 
 // Called when a download delayed by the delegate has completed.
 using DownloadOpenDelayedCallback = base::Callback<void(bool)>;
 
 // Called with the result of CheckForFileExistence().
-using CheckForFileExistenceCallback = base::Callback<void(bool result)>;
+using CheckForFileExistenceCallback = base::OnceCallback<void(bool result)>;
 
 using DownloadIdCallback = base::Callback<void(uint32_t)>;
 
 // Browser's download manager: manages all downloads and destination view.
 class CONTENT_EXPORT DownloadManagerDelegate {
  public:
   // Lets the delegate know that the download manager is shutting down.
   virtual void Shutdown() {}
 
   // Runs |callback| with a new download id when possible, perhaps
@@ skipping 67 matching lines @@
   // relative path.
   virtual void SanitizeSavePackageResourceName(base::FilePath* filename) {}
 
   // Opens the file associated with this download.
   virtual void OpenDownload(DownloadItem* download) {}
 
   // Shows the download via the OS shell.
   virtual void ShowDownloadInShell(DownloadItem* download) {}
 
   // Checks whether a downloaded file still exists.
-  virtual void CheckForFileExistence(
-      DownloadItem* download,
-      const CheckForFileExistenceCallback& callback) {}
+  virtual void CheckForFileExistence(DownloadItem* download,
+                                     CheckForFileExistenceCallback callback) {}
 
   // Return a GUID string used for identifying the application to the system AV
   // function for scanning downloaded files. If no GUID is provided or if the
   // provided GUID is invalid, then the appropriate quarantining will be
   // performed manually without passing the download to the system AV function.
   //
   // This GUID is only used on Windows.
   virtual std::string ApplicationClientIdForFileScanning() const;
 
  protected:
   virtual ~DownloadManagerDelegate();
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_DOWNLOAD_MANAGER_DELEGATE_H_