Converted Observatory nav-menu-item element

runtime/observatory/lib/elements.dart

Index: runtime/observatory/lib/elements.dart
diff --git a/runtime/observatory/lib/elements.dart b/runtime/observatory/lib/elements.dart
index 8066b70fdcd10767df8d51eab1303ade1871e46a..17f191e18881a970daded1d087c312a8ea3c6b63 100644
--- a/runtime/observatory/lib/elements.dart
+++ b/runtime/observatory/lib/elements.dart
@@ -61,14 +61,19 @@ export 'package:observatory/src/elements/vm_view.dart';
 
 import 'dart:async';
 
+import 'package:observatory/src/elements/nav/menu_item.dart';
+import 'package:observatory/src/elements/nav/menu_item_wrapper.dart';
 import 'package:observatory/src/elements/view_footer.dart';
 
 export 'package:observatory/src/elements/helpers/rendering_queue.dart';
 
+export 'package:observatory/src/elements/nav/menu_item.dart';
 export 'package:observatory/src/elements/view_footer.dart';
 
 // Even though this function does not invoke any asynchronous operation
 // it is marked as async to allow future backward compatible changes.
 Future initElements() async {
+  NavMenuItemElement.tag.ensureRegistration();
+  NavMenuItemElementWrapper.tag.ensureRegistration();
   ViewFooterElement.tag.ensureRegistration();
 }