MD Settings: Content Settings: Support guest mode.

chrome/browser/resources/settings/site_settings_page/site_settings_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-site-settings-page' is the settings page containing privacy and
  * security site settings.
  */
 
@@ skipping 16 matching lines @@
       },
     },
 
     /** @private */
     enableSiteSettings_: {
       type: Boolean,
       value: function() {
         return loadTimeData.getBoolean('enableSiteSettings');
       },
     },
+
+    /** @private */
+    isGuest_: {
+      type: Boolean,
+      value: function() { return loadTimeData.getBoolean('isGuest'); }
+    },
   },
 
   /** @override */
   ready: function() {
     this.ContentSettingsTypes = settings.ContentSettingsTypes;
     this.ALL_SITES = settings.ALL_SITES;
 
     var keys = Object.keys(settings.ContentSettingsTypes);
     for (var i = 0; i < keys.length; ++i) {
       var key = settings.ContentSettingsTypes[keys[i]];
       // Default labels are not applicable to USB and ZOOM.
       if (key == settings.ContentSettingsTypes.USB_DEVICES ||
           key == settings.ContentSettingsTypes.ZOOM_LEVELS)
         continue;
+      // Some values are not available (and will DCHECK) in guest mode.
+      if (this.isGuest_ &&
+          key == settings.ContentSettingsTypes.PROTOCOL_HANDLERS) {
+        continue;
+      }
       this.updateDefaultValueLabel_(key);
     }
 
     this.addWebUIListener(
         'contentSettingCategoryChanged',
         this.updateDefaultValueLabel_.bind(this));
     this.addWebUIListener(
         'setHandlersEnabled',
         this.updateHandlersEnabled_.bind(this));
     this.browserProxy.observeProtocolHandlersEnabledState();
@@ skipping 46 matching lines @@
   /**
    * Navigate to the route specified in the event dataset.
    * @param {!Event} event The tap event.
    * @private
    */
   onTapNavigate_: function(event) {
     var dataSet = /** @type {{route: string}} */(event.currentTarget.dataset);
     settings.navigateTo(settings.Route[dataSet.route]);
   },
 });