[MD settings] lighter weight initializer for protocol handler enabled messages

chrome/browser/resources/settings/site_settings/protocol_handlers.js

 // Copyright 2016 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
  * 'protocol-handlers' is the polymer element for showing the
  * protocol handlers category under Site Settings.
  */
 
@@ skipping 46 matching lines @@
     actionMenuModel_: Object
   },
 
   ready: function() {
     this.addWebUIListener('setHandlersEnabled',
         this.setHandlersEnabled_.bind(this));
     this.addWebUIListener('setProtocolHandlers',
         this.setProtocolHandlers_.bind(this));
     this.addWebUIListener('setIgnoredProtocolHandlers',
         this.setIgnoredProtocolHandlers_.bind(this));
-    this.browserProxy.initializeProtocolHandlerList();
+    this.browserProxy.observeProtocolHandlers();
   },
 
   /**
    * Obtains the description for the main toggle.
    * @param {boolean} categoryEnabled Whether the main toggle is enabled.
    * @return {string} The description to use.
    * @private
    */
   computeHandlersDescription_: function(categoryEnabled) {
     var setting = categoryEnabled ?
@@ skipping 91 matching lines @@
    * @private
    */
   showMenu_: function(event) {
     this.actionMenuModel_ = event.model;
     /** @type {!CrActionMenuElement} */ (
         this.$$('dialog[is=cr-action-menu]')).showAt(
             /** @type {!Element} */ (
                 Polymer.dom(/** @type {!Event} */ (event)).localTarget));
   }
 });