DOMUI Prefs: Add a deletable item list type, and use it for startup pages.

chrome/browser/resources/options/browser_options.js

 // Copyright (c) 2010 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 OptionsPage = options.OptionsPage;
   const ArrayDataModel = cr.ui.ArrayDataModel;
   const ListSelectionModel = cr.ui.ListSelectionModel;
 
   //
@@ skipping 335 matching lines @@
      * @private
      */
     updateCustomStartupPageControlStates_: function() {
       var disable = !this.shouldEnableCustomStartupPageControls_();
       $('startupPagesShortList').disabled = disable;
       $('startupUseCurrentButton').disabled = disable;
       $('startupPageManagerButton').disabled = disable;
     },
 
     /**
-     * Removes the selected startup pages.
-     * @private
-     */
-    removeSelectedStartupPages_: function() {
-      var selections =
-          $('startupPagesShortList').selectionModel.selectedIndexes.map(String);
-      chrome.send('removeStartupPages', selections);
-    },
-
-    /**
-     * Adds the given startup page at the current selection point.
-     * @private
-     */
-    addStartupPage_: function(url) {
-      var firstSelection =
-          $('startupPagesShortList').selectionModel.selectedIndex;
-      chrome.send('addStartupPage', [url, String(firstSelection)]);
-    },
-
-    /**
      * Set the default search engine based on the popup selection.
      */
     setDefaultSearchEngine: function() {
       var engineSelect = $('defaultSearchEngine');
       var selectedIndex = engineSelect.selectedIndex;
       if (selectedIndex >= 0) {
         var selection = engineSelect.options[selectedIndex];
         chrome.send('setDefaultSearchEngine', [String(selection.value)]);
       }
     },
@@ skipping 10 matching lines @@
 
   BrowserOptions.updateSearchEngines = function(engines, defaultValue) {
     BrowserOptions.getInstance().updateSearchEngines_(engines, defaultValue);
   };
 
   BrowserOptions.updateStartupPages = function(pages) {
     BrowserOptions.getInstance().updateStartupPages_(pages);
     StartupPageManager.getInstance().updateStartupPages_(pages);
   };
 
-  BrowserOptions.addStartupPage = function(url) {
-    BrowserOptions.getInstance().addStartupPage_(url);
-  };
-
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 
 });