Remove all ReadingList entries on managed account signout.

ios/chrome/browser/reading_list/url_downloader.h

 // Copyright 2016 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 IOS_CHROME_BROWSER_READING_LIST_URL_DOWNLOADER_H_
 #define IOS_CHROME_BROWSER_READING_LIST_URL_DOWNLOADER_H_
 
 #include <queue>
 
 #include "base/callback.h"
@@ skipping 79 matching lines @@
 
   // Cancels the download job an offline version of the URL.
   void CancelDownloadOfflineURL(const GURL& url);
 
   // Asynchronously remove the offline version of the URL if it exists.
   void RemoveOfflineURL(const GURL& url);
 
   // URLFetcherDelegate delegate method.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
+  // Cancels the current download task.
+  void CancelTask();
+
  private:
   enum TaskType { DELETE, DOWNLOAD };
   using Task = std::pair<TaskType, GURL>;
 
   // Calls callback with true if an offline path exists. |path| must be
   // absolute.
   void OfflinePathExists(const base::FilePath& url,
                          base::Callback<void(bool)> callback);
   // Handles the next task in the queue, if no task is currently being handled.
   void HandleNextTask();
@@ skipping 78 matching lines @@
   std::unique_ptr<net::URLFetcher> fetcher_;
   // URLRequestContextGetter needed for the URLFetcher.
   scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
   std::unique_ptr<dom_distiller::DistillerViewerInterface> distiller_;
   base::CancelableTaskTracker task_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(URLDownloader);
 };
 
 #endif  // IOS_CHROME_BROWSER_READING_LIST_URL_DOWNLOADER_H_