Use words please.

runtime/observatory/lib/src/elements/nav_bar.dart

 // Copyright (c) 2013, 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.
 
 library nav_bar_element;
 
 import 'dart:async';
-import 'dart:html';
+import 'dart:html' hide Notification;
 import 'observatory_element.dart';
 import 'package:observatory/service.dart';
+import 'package:observatory/app.dart' show Notification;
 import 'package:polymer/polymer.dart';
 
 
 @CustomTag('nav-bar')
 class NavBarElement extends ObservatoryElement {
   @published bool notifyOnPause = true;
   @published bool pad = true;
 
   NavBarElement.created() : super.created();
 }
@@ skipping 122 matching lines @@
   @observable get isUnexpectedError {
     return (exception is! NetworkRpcException);
   }
 
   void closeItem(MouseEvent e, var detail, Element target) {
     notifications.remove(notification);
   }
 
   NavNotifyExceptionElement.created() : super.created();
 }