[MD settings] fixes for OnStartup using the closure compiler

chrome/browser/resources/settings/on_startup_page/startup_urls_page.js

 // Copyright 2015 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 'cr-settings-startup-urls-page' is the settings page
  * containing the urls that will be opened when chrome is started.
  *
  * Example:
  *
@@ skipping 26 matching lines @@
     savedUrlList: {
       type: Array,
     },
   },
 
   observers: [
     'prefsChanged_(prefs.session.startup_urls.value.*)',
   ],
 
   attached: function() {
-    var updateFunction = this.updateStartupPages_.bind(this);
+    var self = this;
     cr.define('Settings', function() {
       return {
-        updateStartupPages: updateFunction,
+        updateStartupPages: function() {
+          return self.updateStartupPages_.apply(self, arguments);
+        },
       };
     });
   },
 
+
   /** @private */
   prefsChanged_: function(change) {
-    if (this.savedUrlList == undefined &&
-        this.get('prefs.session.startup_urls')) {
-      this.savedUrlList = this.prefs.session.startup_urls.value.slice();
-    }
+    var pref = /** @type {chrome.settingsPrivate.PrefObject} */(
+        this.get('prefs.session.startup_urls'));
+    if (!this.savedUrlList && pref)
+      this.savedUrlList = pref.value.slice();

[Dan Beam, 2015/09/18 19:05:53]

nit: try to use variables as close as you can to where they're declared.  in
this case, the optimal code (for never doing any needless work) is, imo:

if (!this.savedUrlList) {
  var pref = this.get('prefs.session.startup_urls');
  if (pref)
    this.savedUrlList = pref.value.slice();
}

or

if (this.savedUrlList)
  return;

var pref = this.get('prefs.session.startup_urls');
if (pref)
  this.savedUrlList = pref.value.slice();

   },
 
   /** @private */
   updateStartupPages_: function(data) {
     var urlArray = [];
     for (var i = 0; i < data.length; ++i)
       urlArray.push(data[i].url);
     this.set('prefs.session.startup_urls.value', urlArray);
   },
 
@@ skipping 19 matching lines @@
   },
 
   /**
    * @param {!{model: !{index: number}}} e
    * @private
    */
   onRemoveUrlTap_: function(e) {
     this.splice('prefs.session.startup_urls.value', e.model.index, 1);
   },
 });