[New Tab Page] Add aria-hidden to an element.

chrome/browser/resources/local_ntp/local_ntp.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 The local InstantExtended NTP.
  */
 
 
@@ skipping 707 matching lines @@
     if (NTP_DESIGN.thumbnailFallback) {
       var fallbackElem = createAndAppendElement(
           innerElem, 'div', CLASSES.THUMBNAIL_FALLBACK);
       if (NTP_DESIGN.thumbnailFallback === THUMBNAIL_FALLBACK.DOT)
         createAndAppendElement(fallbackElem, 'div', CLASSES.DOT);
     }
 
     // The iframe which renders either a thumbnail or domain element.
     var thumbnailElem = document.createElement('iframe');
     thumbnailElem.tabIndex = '-1';
+    thumbnailElem.setAttribute('aria-hidden', 'true');
     // Keep this ID here. See comment above.
     thumbnailElem.id = 'thumb-' + rid;
     thumbnailElem.className = CLASSES.THUMBNAIL;
     thumbnailElem.src = getMostVisitedThumbnailIframeUrl(rid, position);
     innerElem.appendChild(thumbnailElem);
 
     // The button used to blacklist this page.
     var blacklistButton = createAndAppendElement(
         innerElem, 'div', CLASSES.BLACKLIST_BUTTON);
     createAndAppendElement(
@@ skipping 18 matching lines @@
   } else {
     return new Tile(tileElem);
   }
 }
 
 
 /**
  * Generates a function to be called when the page with the corresponding RID
  * is blacklisted.
  * @param {number} rid The RID of the page being blacklisted.
- * @return {function(!Event)} A function which handles the blacklisting of the
+ * @return {function(Event=)} A function which handles the blacklisting of the
  *     page by updating state variables and notifying Chrome.
  */
 function generateBlacklistFunction(rid) {
   return function(e) {
     // Prevent navigation when the page is being blacklisted.
     if (e)
       e.stopPropagation();
 
     userInitiatedMostVisitedChange = true;
     isBlacklisting = true;
@@ skipping 418 matching lines @@
 
 return {
   init: init,
   listen: listen
 };
 }
 
 if (!window.localNTPUnitTest) {
   LocalNTP().listen();
 }