[MD settings] move <dialog> out of content

chrome/browser/resources/settings/controls/settings_toggle_button.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
  * `settings-toggle-button` is a toggle that controls a supplied preference.
  */
 Polymer({
   is: 'settings-toggle-button',
 
+  behaviors: [SettingsBooleanControlBehavior],
+
   properties: {
     elideLabel: {
       type: Boolean,
       reflectToAttribute: true,
     },
   },
 
-  behaviors: [SettingsBooleanControlBehavior],
+  /** @override */
+  focus: function() {
+    this.$.control.focus();
+  },
 
   /** @private */
   onLabelWrapperTap_: function() {
     if (this.controlDisabled_())
       return;
 
     this.checked = !this.checked;
     this.notifyChangedByUserInteraction();
   },
 });