Fix JS whoopsies from https://crrev.com/e2f61d09c3f

chrome/browser/resources/options/automatic_settings_reset_banner.js

 // Copyright 2014 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.
 
 // Note: the native-side handler for this is AutomaticSettingsResetHandler.
 
 cr.define('options', function() {
   /** @const */ var PageManager = cr.ui.pageManager.PageManager;
 
   /**
    * AutomaticSettingsResetBanner class
    * Provides encapsulated handling of the Reset Profile Settings banner.
    * @constructor
-   * @extends {options.SettingsBannerBase}
    */
   function AutomaticSettingsResetBanner() {}
 
   cr.addSingletonGetter(AutomaticSettingsResetBanner);
 
   AutomaticSettingsResetBanner.prototype = {
     /**
      * Whether or not the banner has already been dismissed.
      *
      * This is needed because of the surprising ordering of asynchronous
      * JS<->native calls when the settings page is opened with specifying a
      * given sub-page, e.g. chrome://settings/AutomaticSettingsReset.
      *
      * In such a case, AutomaticSettingsResetOverlay's didShowPage(), which
      * calls our dismiss() method, would be called before the native Handlers'
      * InitalizePage() methods have an effect in the JS, which includes calling
      * our show() method. This would mean that the banner would be first
      * dismissed, then shown. We want to prevent this.
      *
-     * @type {boolean}
-     * @private
+     * @private {boolean}
      */
-    hadBeenDismissed_: false,
+    wasDismissed_: false,
 
     /**
      * Metric name to send when a show event occurs.
+     * @private {string}
      */
     showMetricName_: '',
 
     /**
      * Name of the native callback invoked when the banner is dismised.
      */
     dismissNativeCallbackName_: '',
 
     /**
      * DOM element whose visibility is set when setVisibility_ is called.
+     * @private {?HTMLElement}
      */
-    setVisibilibyDomElement_: null,
+    visibleElement_: null,
 
     /**
      * Initializes the banner's event handlers.
      * @suppress {checkTypes}
      * TODO(vitalyp): remove the suppression. Suppression is needed because
      * method dismiss() is attached to AutomaticSettingsResetBanner at run-time
      * via "Forward public APIs to protected implementations" pattern (see
      * below). Currently the compiler pass and cr.js handles only forwarding to
      * private implementations using cr.makePublic().
      */
     initialize: function() {
       this.showMetricName_ = 'AutomaticSettingsReset_WebUIBanner_BannerShown';
 
       this.dismissNativeCallbackName_ =
           'onDismissedAutomaticSettingsResetBanner';
 
-      this.setVisibilibyDomElement_ = $('automatic-settings-reset-banner');
+      this.visibleElement_ = getRequiredElement(
+          'automatic-settings-reset-banner');
 
       $('automatic-settings-reset-banner-close').onclick = function(event) {
         chrome.send('metricsHandler:recordAction',
             ['AutomaticSettingsReset_WebUIBanner_ManuallyClosed']);
         AutomaticSettingsResetBanner.dismiss();
       };
       $('automatic-settings-reset-learn-more').onclick = function(event) {
         chrome.send('metricsHandler:recordAction',
             ['AutomaticSettingsReset_WebUIBanner_LearnMoreClicked']);
       };
       $('automatic-settings-reset-banner-activate-reset').onclick =
           function(event) {
         chrome.send('metricsHandler:recordAction',
             ['AutomaticSettingsReset_WebUIBanner_ResetClicked']);
         PageManager.showPageByName('resetProfileSettings');
       };
     },
 
     /**
      * Sets whether or not the reset profile settings banner shall be visible.
      * @param {boolean} show Whether or not to show the banner.
      * @protected
      */
     setVisibility: function(show) {
-      this.setVisibilibyDomElement_.hidden = !show;
+      this.visibleElement_.hidden = !show;
     },
 
     /**
      * Called by the native code to show the banner if needed.
      * @private
      */
     show_: function() {
-      if (!this.hadBeenDismissed_) {
+      if (!this.wasDismissed_) {
         chrome.send('metricsHandler:recordAction', [this.showMetricName_]);
         this.setVisibility(true);
       }
     },
 
     /**
      * Called when the banner should be closed as a result of something taking
      * place on the WebUI page, i.e. when its close button is pressed, or when
      * the confirmation dialog for the profile settings reset feature is opened.
      * @private
      */
     dismiss_: function() {
-      chrome.send(this.dismissNativeCallbackName_);
-      this.hadBeenDismissed_ = true;
+      chrome.send(assert(this.dismissNativeCallbackName_));
+      this.wasDismissed_ = true;
       this.setVisibility(false);
     },
   };
 
   // Forward public APIs to private implementations.
   cr.makePublic(AutomaticSettingsResetBanner, [
     'show',
     'dismiss',
   ]);
 
   // Export
   return {
     AutomaticSettingsResetBanner: AutomaticSettingsResetBanner
   };
 });