md-settings: wrap lock screen dialogs in dom-if.

chrome/browser/resources/settings/people_page/setup_pin_dialog.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-setup-pin-dialog' is the settings page for choosing a PIN.
  *
  * Example:
- *
- * <settings-setup-pin-dialog set-modes="[[quickUnlockSetModes]]">
+ * * <settings-setup-pin-dialog set-modes="[[quickUnlockSetModes]]">
  * </settings-setup-pin-dialog>
  */
 
 (function() {
 'use strict';
 
 /**
  * Keep in sync with the string keys provided by settings.
  * @enum {string}
  */
@@ skipping 72 matching lines @@
      */
     quickUnlockPrivate_: {
       type: Object,
       value: chrome.quickUnlockPrivate
     },
   },
 
   /** @override */
   attached: function() {
     this.resetState_();
-  },
-
-  open: function() {
     this.$.dialog.showModal();
-    this.$.pinKeyboard.focus();
   },
 
   close: function() {
     if (this.$.dialog.open)
       this.$.dialog.close();
 
     this.resetState_();
   },
 
   /**
@@ skipping 150 matching lines @@
       return;
     }
 
     function onSetModesCompleted(didSet) {
       if (!didSet) {
         console.error('Failed to update pin');
         return;
       }
 
       this.resetState_();
-      this.fire('done');
+      if (this.$.dialog.open)
+        this.$.dialog.close();
     }
 
     this.setModes.call(
       null,
       [chrome.quickUnlockPrivate.QuickUnlockMode.PIN],
       [this.pinKeyboardValue_],
       onSetModesCompleted.bind(this));
     this.writeUma_(LockScreenProgress.CONFIRM_PIN);
   },
 
@@ skipping 21 matching lines @@
    * @private
    * @param {boolean} isConfirmStep
    * @return {string}
    */
   getContinueMessage_: function(isConfirmStep) {
     return this.i18n(isConfirmStep ? 'confirm' : 'configurePinContinueButton');
   },
 });
 
 })();