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

chrome/browser/resources/settings/site_settings/media_picker.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
  * 'media-picker' handles showing the dropdown allowing users to select the
  * default camera/microphone.
  */
 Polymer({
@@ skipping 10 matching lines @@
     /** Label for a11y purposes. */
     label: String,
 
     /**
      * The devices available to pick from.
      * @type {Array<MediaPickerEntry>}
      */
     devices: Array,
   },
 
+  /** @override */
   ready: function() {
     this.addWebUIListener('updateDevicesMenu',
         this.updateDevicesMenu_.bind(this));
     this.browserProxy.getDefaultCaptureDevices(this.type);
   },
 
   /**
    * Updates the microphone/camera devices menu with the given entries.
    * @param {string} type The device type.
    * @param {!Array<MediaPickerEntry>} devices List of available devices.
@@ skipping 16 matching lines @@
 
   /**
    * A handler for when an item is selected in the media picker.
    * @private
    */
   onChange_: function() {
     this.browserProxy.setDefaultCaptureDevice(
         this.type, this.$.mediaPicker.value);
   },
 });