MD User Manager: Refactors existing dialogs in User Manager into <user-manager-dialog>

chrome/browser/resources/md_user_manager/error_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 'error-dialog' is a popup dialog that displays error messages
+ * @fileoverview 'error-dialog' is a dialog that displays error messages
  * in the user manager.
  */
 (function() {
 Polymer({
   is: 'error-dialog',
 
   properties: {
     /**
-     * True if the element is currently hidden.
-     * @private {boolean}
-     */
-    popupHidden_: {
-      type: Boolean,
-      value: true
-    },
-
-    /**
      * The message shown in the dialog.
      * @private {string}
      */
     message_: {
       type: String,
       value: ''
     }
   },
 
   /**
-   * Displays the popup populated with the given message.
+   * Displays the dialog populated with the given message.
    * @param {string} message Error message to show.
    */
   show: function(message) {
     this.message_ = message;
-    this.popupHidden_ = false;
-
-    this.async(function() {
-      this.$$('paper-icon-button').focus();
-    }.bind(this));
-  },
-
-  /**
-   * Hides the popup.
-   * @private
-   */
-  onCloseTap_: function() {
-    this.popupHidden_ = true;
+    this.$.dialog.open();
   }
 });
 })();