Centralized event streams

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/rendering_scheduler.dart';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/uris.dart';
 import 'package:observatory/src/elements/nav/menu.dart';
 import 'package:observatory/src/elements/nav/menu_item.dart';
 
 class NavTopMenuElement extends HtmlElement implements Renderable {
   static const tag = const Tag<NavTopMenuElement>('nav-top-menu',
                      dependencies: const [NavMenuElement.tag,
                                           NavMenuItemElement.tag]);
 
   RenderingScheduler _r;
 
   Stream<RenderedEvent<NavTopMenuElement>> get onRendered => _r.onRendered;
 
   bool _last;
+  
   bool get last => _last;
+
   set last(bool value) => _last = _r.checkAndReact(_last, value);
 
   factory NavTopMenuElement({bool last: false, RenderingQueue queue}) {
     assert(last != null);
     NavTopMenuElement e = document.createElement(tag.name);
     e._r = new RenderingScheduler(e, queue: queue);
     e._last = last;
     return e;
   }
 
@@ skipping 17 matching lines @@
       new NavMenuElement('Observatory', link: Uris.vm(), last: last,
                          queue: _r.queue)
         ..children = [
           new NavMenuItemElement('Connect to a VM', link: Uris.vmConnect(),
                                  queue: _r.queue),
           new ContentElement()
         ]
     ];
   }
 }