Added missing content to nav-top-menu

runtime/observatory/lib/src/elements/nav/top_menu.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/src/elements/helpers/nav_menu.dart';
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/uris.dart';
@@ skipping 35 matching lines @@
     super.detached();
     _r.disable(notify: true);
     children = [];
   }
 
   void render() {
     final content = ([
       new NavMenuItemElement('Connect to a VM', link: Uris.vmConnect()),
     ]..addAll(_content));
     children = [
-      navMenu('Observatory', link: Uris.vm(), content: _content)
+      navMenu('Observatory', link: Uris.vm(), content: content)
     ];
   }
 }