[Files app] ES6 for ui/file_manager/file_manager/foreground/js/ui/files_alert_dialog.js

Bug: 778674
Change-Id: I1c6dce2dcb7424fc6cab9faa10a1b510396b78b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619526
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Auto-Submit: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661279}

ui/file_manager/file_manager/foreground/js/ui/files_alert_dialog.js

@@ -4,21 +4,21 @@
 
 /**
  * Alert dialog.
+ */
+class FilesAlertDialog extends cr.ui.dialogs.AlertDialog {
+  /**
    * @param {!HTMLElement} parentNode
- * @constructor
- * @extends {cr.ui.dialogs.AlertDialog}
    */
-const FilesAlertDialog = function(parentNode) {
-  cr.ui.dialogs.AlertDialog.call(this, parentNode);
-};
-
-FilesAlertDialog.prototype.__proto__ = cr.ui.dialogs.AlertDialog.prototype;
+  constructor(parentNode) {
+    super(parentNode);
+  }
 
-/**
+  /**
    * @protected
    * @override
    */
-FilesAlertDialog.prototype.initDom_ = function() {
-  cr.ui.dialogs.AlertDialog.prototype.initDom_.call(this);
+  initDom_() {
+    super.initDom_();
     this.frame_.classList.add('files-alert-dialog');
-};
+  }
+}