Settings: Network: Handle getmanagerProperties error correctly

chrome/browser/resources/settings/internet_page/internet_known_networks_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
  * 'settings-internet-known-networks' is the settings subpage listing the
  * known networks for a type (currently always WiFi).
  */
 Polymer({
@@ skipping 136 matching lines @@
   onMenuButtonTap_: function(event) {
     var button = /** @type {!HTMLElement} */ (event.target);
     this.selectedGuid_ =
         /** @type {!{model: !{item: !CrOnc.NetworkStateProperties}}} */ (event)
             .model.item.GUID;
     // We need to make a round trip to Chrome in order to retrieve the managed
     // properties for the network. The delay is not noticeable (~5ms) and is
     // preferable to initiating a query for every known network at load time.
     this.networkingPrivate.getManagedProperties(
         this.selectedGuid_, function(properties) {
+          if (chrome.runtime.lastError || !properties) {
+            this.showAddPreferred_ = false;
+            this.showRemovePreferred_ = false;
+            return;
+          }
           var preferred = button.hasAttribute('preferred');
           if (this.isNetworkPolicyEnforced(properties.Priority)) {
             this.showAddPreferred_ = false;
             this.showRemovePreferred_ = false;
           } else {
             this.showAddPreferred_ = !preferred;
             this.showRemovePreferred_ = preferred;
           }
           /** @type {!CrActionMenuElement} */ (this.$.dotsMenu).showAt(button);
         }.bind(this));
@@ skipping 25 matching lines @@
    * @private
    */
   fireShowDetails_: function(event) {
     var state =
         /** @type {!{model: !{item: !CrOnc.NetworkStateProperties}}} */ (event)
             .model.item;
     this.fire('show-detail', state);
     event.stopPropagation();
   },
 });