[MD settings] cast elements to cr_dialog

chrome/browser/resources/settings/certificate_manager_page/certificate_delete_confirmation_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 A confirmation dialog allowing the user to delete various types
  * of certificates.
  */
 Polymer({
   is: 'settings-certificate-delete-confirmation-dialog',
 
   properties: {
     /** @private {!settings.CertificatesBrowserProxy} */
     browserProxy_: Object,
 
     /** @type {!CertificateSubnode} */
     model: Object,
 
     /** @type {!CertificateType} */
     certificateType: String,
   },
 
   /** @override */
   ready: function() {
     this.browserProxy_ = settings.CertificatesBrowserProxyImpl.getInstance();
   },
 
   /** @override */
   attached: function() {
-    this.$.dialog.open();
+    /** @type {!CrDialogElement} */ (this.$.dialog).open();
   },
 
   /**
    * @private
    * @return {string}
    */
   getTitleText_: function() {
     /**
      * @param {string} localizedMessageId
      * @return {string}
@@ skipping 29 matching lines @@
       case CertificateType.CA:
         return getString('certificateManagerDeleteCaDescription');
       case CertificateType.OTHER:
         return '';
     }
     assertNotReached();
   },
 
   /** @private */
   onCancelTap_: function() {
-    this.$.dialog.close();
+    /** @type {!CrDialogElement} */ (this.$.dialog).close();
   },
 
   /** @private */
   onOkTap_: function() {
     this.browserProxy_.deleteCertificate(this.model.id).then(
         function() {
-          this.$.dialog.close();
+          /** @type {!CrDialogElement} */ (this.$.dialog).close();
         }.bind(this),
         /** @param {!CertificatesError} error */
         function(error) {
-          this.$.dialog.close();
+          /** @type {!CrDialogElement} */ (this.$.dialog).close();
           this.fire('certificates-error', error);
         }.bind(this));
   },
 });