Options: Remove the hidden class, since we override the hidden attribute to set

chrome/browser/resources/options/content_settings_exceptions_area.js

 // Copyright (c) 2011 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.
 
 cr.define('options.contentSettings', function() {
   const InlineEditableItemList = options.InlineEditableItemList;
   const InlineEditableItem = options.InlineEditableItem;
   const ArrayDataModel = cr.ui.ArrayDataModel;
 
   /**
@@ skipping 487 matching lines @@
      * Shows one list and hides all others.
      * @param {string} type The content type.
      */
     showList: function(type) {
       var header = this.pageDiv.querySelector('h1');
       header.textContent = templateData[type + '_header'];
 
       var divs = this.pageDiv.querySelectorAll('div[contentType]');
       for (var i = 0; i < divs.length; i++) {
         if (divs[i].getAttribute('contentType') == type)
-          divs[i].classList.remove('hidden');
+          divs[i].hidden = false;
         else
-          divs[i].classList.add('hidden');
+          divs[i].hidden = true;
       }
     },
 
     /**
      * Called after the page has been shown. Show the content type for the
      * location's hash.
      */
     didShowPage: function() {
       var hash = location.hash;
       if (hash)
         this.showList(hash.slice(1));
     },
   };
 
   /**
    * Called when the last incognito window is closed.
    */
   ContentSettingsExceptionsArea.OTRProfileDestroyed = function() {
     this.hideOTRLists();
   };
 
   /**
    * Clears and hides the incognito exceptions lists.
    */
   ContentSettingsExceptionsArea.hideOTRLists = function() {
     var otrLists = document.querySelectorAll('list[mode=otr]');
 
     for (var i = 0; i < otrLists.length; i++) {
       otrLists[i].reset();
-      otrLists[i].parentNode.classList.add('hidden');
+      otrLists[i].parentNode.hidden = true;
     }
   };
 
   return {
     ExceptionsListItem: ExceptionsListItem,
     ExceptionsAddRowListItem: ExceptionsAddRowListItem,
     ExceptionsList: ExceptionsList,
     ContentSettingsExceptionsArea: ContentSettingsExceptionsArea,
   };
 });