[MD settings] specify @override on created, ready, and attached

chrome/browser/resources/settings/site_settings/zoom_levels.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
  * 'zoom-levels' is the polymer element for showing the sites that are zoomed in
  * or out.
  */
 
 Polymer({
   is: 'zoom-levels',
 
   behaviors: [SiteSettingsBehavior, WebUIListenerBehavior],
 
   properties: {
     /**
      * Array of sites that are zoomed in or out.
      * @type {!Array<ZoomLevelEntry>}
      */
     sites_: Array,
   },
 
+  /** @override */
   ready: function() {
     this.addWebUIListener('onZoomLevelsChanged',
         this.onZoomLevelsChanged_.bind(this));
     this.browserProxy.fetchZoomLevels();
   },
 
   /**
    * A handler for when zoom levels change.
    * @param {!Array<ZoomLevelEntry>} sites The up to date list of sites and
    *     their zoom levels.
    */
   onZoomLevelsChanged_: function(sites) {
     this.sites_ = sites;
   },
 
   /**
    * A handler for when a zoom level for a site is deleted.
    * @param {!{model: !{index: number}}} event
    * @private
    */
-   removeZoomLevel_: function(event) {
-     var site = this.sites_[event.model.index];
-     this.browserProxy.removeZoomLevel(site.origin);
+  removeZoomLevel_: function(event) {
+    var site = this.sites_[event.model.index];
+    this.browserProxy.removeZoomLevel(site.origin);
   },
 });