Use a new flag to control showing "DOWNLOAD PAGE LATER" in error pages

components/error_page/common/localized_error.cc

 // 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.
 
 #include "components/error_page/common/localized_error.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 981 matching lines @@
         "title",
         l10n_util::GetStringUTF16(IDS_ERRORPAGES_BUTTON_SHOW_SAVED_COPY_HELP));
     if (show_saved_copy_primary)
       show_saved_copy_button->SetString("primary", "true");
     error_strings->Set("showSavedCopyButton", show_saved_copy_button);
   }
 
 #if defined(OS_ANDROID)
   if (!show_saved_copy_visible &&
       failed_url.SchemeIsHTTPOrHTTPS() &&
-      offline_pages::IsOfflinePagesBackgroundLoadingEnabled()) {
+      offline_pages::IsOfflinePagesAsyncDownloadEnabled()) {
     std::unique_ptr<base::DictionaryValue> download_button =
         base::MakeUnique<base::DictionaryValue>();
     download_button->SetString(
         "msg",
         l10n_util::GetStringUTF16(IDS_ERRORPAGES_BUTTON_DOWNLOAD));
     download_button->SetString(
         "disabledMsg",
         l10n_util::GetStringUTF16(IDS_ERRORPAGES_BUTTON_DOWNLOADING));
     error_strings->Set("downloadButton", std::move(download_button));
   }
@@ skipping 13 matching lines @@
 
 bool LocalizedError::HasStrings(const std::string& error_domain,
                                 int error_code) {
   // Whether or not the there are strings for an error does not depend on
   // whether or not the page was be generated by a POST, so just claim it was
   // not.
   return LookupErrorMap(error_domain, error_code, /*is_post=*/false) != nullptr;
 }
 
 }  // namespace error_page