[MD settings] update protocol handler setting in content settings

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.
  */
 Polymer({
@@ skipping 17 matching lines @@
 
     /** @private */
     enableSiteSettings_: {
       type: Boolean,
       value: function() {
         return loadTimeData.getBoolean('enableSiteSettings');
       },
     },
   },
 
+  /** @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;
       this.updateDefaultValueLabel_(key);
     }
 
     this.addWebUIListener(
         'contentSettingCategoryChanged',
         this.updateDefaultValueLabel_.bind(this));
+    this.addWebUIListener(
+        'setHandlersEnabled',
+        this.updateHandlersEnabled_.bind(this));
+    this.browserProxy.observeProtocolHandlersEnabledState();
   },
 
   /**
    * @param {string} category The category to update.
    * @private
    */
   updateDefaultValueLabel_: function(category) {
     this.browserProxy.getDefaultValueForContentType(
         category).then(function(defaultValue) {
-          var labelVar =
-              'default_.' + Polymer.CaseMap.dashToCamelCase(category);
           this.set(
-              labelVar,
+              'default_.' + Polymer.CaseMap.dashToCamelCase(category),
               this.computeCategoryDesc(
                   category,
                   defaultValue.setting,
                   /*showRecommendation=*/false));
         }.bind(this));
   },
 
   /**
+   * The protocol handlers have a separate enabled/disabled notifier.
+   * @param {boolean} enabled
+   * @private
+   */
+  updateHandlersEnabled_: function(enabled) {
+    var category = settings.ContentSettingsTypes.PROTOCOL_HANDLERS;
+    this.set(
+        'default_.' + Polymer.CaseMap.dashToCamelCase(category),
+        this.computeCategoryDesc(
+            category,
+            enabled ?
+                settings.PermissionValues.ALLOW :
+                settings.PermissionValues.BLOCK,
+            /*showRecommendation=*/false));
+  },
+
+  /**
    * 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]);
   },
 });