fix appearance of buttons in chrome://settings

chrome/browser/resources/options/deletable_item_list.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', function() {
   const List = cr.ui.List;
   const ListItem = cr.ui.ListItem;
 
   /**
    * Creates a deletable list item, which has a button that will trigger a call
@@ skipping 28 matching lines @@
     /** @inheritDoc */
     decorate: function() {
       ListItem.prototype.decorate.call(this);
 
       this.classList.add('deletable-item');
 
       this.contentElement_ = this.ownerDocument.createElement('div');
       this.appendChild(this.contentElement_);
 
       this.closeButtonElement_ = this.ownerDocument.createElement('button');
-      this.closeButtonElement_.classList.add('raw-button');
-      this.closeButtonElement_.classList.add('close-button');
+      this.closeButtonElement_.className =
+          'raw-button close-button custom-appearance';
       this.closeButtonElement_.addEventListener('mousedown',
                                                 this.handleMouseDownUpOnClose_);
       this.closeButtonElement_.addEventListener('mouseup',
                                                 this.handleMouseDownUpOnClose_);
       this.closeButtonElement_.addEventListener('focus',
                                                 this.handleFocus_.bind(this));
       this.appendChild(this.closeButtonElement_);
     },
 
     /**
@@ skipping 115 matching lines @@
      */
     deleteItemAtIndex: function(index) {
     },
   };
 
   return {
     DeletableItemList: DeletableItemList,
     DeletableItem: DeletableItem,
   };
 });