[IOS Reading List] Change handling of distillation error.

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 30 matching lines @@
                       reading_list::ReadingListDistillerPageDelegate {
   friend class MockURLDownloader;
 
  public:
   // And enum indicating different download outcomes.
   enum SuccessState {
     // The URL was correctly downloaded and an offline version is not available.
     DOWNLOAD_SUCCESS,
     // The URL was already available offline. No action was done.
     DOWNLOAD_EXISTS,
-    // The URL could not be downloaded because of a temporary error. Client may
-    // want to try again later.
-    ERROR_RETRY,
-    // The URL could not be dowmloaded and URLDownloader thinks a retry would
-    // end with the same result. There is no need to retry.
-    ERROR_PERMANENT
+    // The URL could not be downloaded because of an error. Client may want to
+    // try again later.
+    ERROR,
   };
 
   // A completion callback that takes a GURL and a bool indicating the
   // outcome and returns void.
   using SuccessCompletion = base::Callback<void(const GURL&, bool)>;
 
   // A download completion callback that takes, in order, the GURL that was
   // downloaded, the GURL of the page that was downloaded after redirections, a
   // SuccessState indicating the outcome of the download, the path to the
   // downloaded page (relative to |OfflineRootDirectoryPath()|, and the title of
@@ skipping 122 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_