Upgrade checkbox, pref-tracker, and prefs to 0.8

chrome/browser/resources/settings/checkbox/checkbox.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
  * `cr-settings-checkbox` is a checkbox that controls a supplied preference.
  *
  * Example:
  *      <cr-settings-checkbox pref="{{prefs.settings.enableFoo}}"
  *          label="Enable foo setting." subLabel="(bar also)">
  *      </cr-settings-checkbox>
  *
  * @element cr-settings-checkbox
  */
 Polymer({
-  publish: {
+  is: 'cr-settings-checkbox',
+
+  properties: {
     /**
-     * The boolean preference to control.
-     *
-     * @attribute pref
-     * @type {Object}
-     * @default null
+     * The boolean preference object to control.
+     * @type {?chrome.settingsPrivate.PrefObject}
      */
-    pref: null,
+    pref: Object,
 
-    /**
-     * @attribute label
-     * @type {string}
-     * @default ''
-     */
-    label: '',
+    label: {
+      type: String,
+      value: '',
+    },
 
-    /**
-     * @attribute label
-     * @type {string}
-     * @default ''
-     */
-    subLabel: '',
+    subLabel: {
+      type: String,
+      value: '',
+    },
   },
 
+  /** @override */
   ready: function() {
     this.$.events.forward(this.$.checkbox, ['change']);
   },
 });