NTP thumbnails: Always pass singular "thumbnailUrl" to the iframe

chrome/browser/resources/local_ntp/most_visited_thumbnail.js

 // Copyright 2013 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.
 
 
 /**
  * @fileoverview Rendering for iframed most visited thumbnails.
  */
 
 window.addEventListener('DOMContentLoaded', function() {
@@ skipping 40 matching lines @@
           showDomainElement();
         } else {
           showEmptyTile();
         }
       };
       image.src = src;
     }
 
     if (data.dummy) {
       showEmptyTile();
-    } else if (data.thumbnailUrls && data.thumbnailUrls.length) {
-      createThumbnail(data.thumbnailUrls[0], 'thumbnail');
+    } else if (data.thumbnailUrl) {
+      createThumbnail(data.thumbnailUrl, 'thumbnail');
     } else if (data.domain) {
       showDomainElement();
     } else {
       showEmptyTile();
     }
   });
 });