Making the selectedIndex property setters of ListSelectionModel and ListSingleSelectionModel behave…

chrome/browser/resources/options/language_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 ArrayDataModel = cr.ui.ArrayDataModel;
   const DeletableItem = options.DeletableItem;
   const DeletableItemList = options.DeletableItemList;
   const List = cr.ui.List;
   const ListItem = cr.ui.ListItem;
@@ skipping 387 matching lines @@
       // Preserve the original selected index. See comments below.
       var originalSelectedIndex = (this.selectionModel ?
                                    this.selectionModel.selectedIndex : -1);
       this.dataModel = new ArrayDataModel(languageCodes);
       if (originalSelectedIndex >= 0 &&
           originalSelectedIndex < this.dataModel.length) {
         // Restore the original selected index if the selected index is
         // valid after the data model is loaded. This is neeeded to keep
         // the selected language after the languge is added or removed.
         this.selectionModel.selectedIndex = originalSelectedIndex;
-        // The lead index should be updated too.
-        this.selectionModel.leadIndex = originalSelectedIndex;
       } else if (this.dataModel.length > 0){
         // Otherwise, select the first item if it's not empty.
         // Note that ListSingleSelectionModel won't select an item
         // automatically, hence we manually select the first item here.
         this.selectionModel.selectedIndex = 0;
       }
     },
 
     /**
      * Saves the preference.
@@ skipping 58 matching lines @@
       }
       return filteredLanguageCodes;
     },
   };
 
   return {
     LanguageList: LanguageList,
     LanguageListItem: LanguageListItem
   };
 });