Centralized event streams

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

 // Copyright (c) 2015, 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 view_footer_element;
 
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
 
 class ViewFooterElement extends HtmlElement implements Renderable {
   static const tag = const Tag<ViewFooterElement>('view-footer');
 
   RenderingScheduler _r;
 
   Stream<RenderedEvent<ViewFooterElement>> get onRendered => _r.onRendered;
 
   factory ViewFooterElement({RenderingQueue queue}) {
     ViewFooterElement e = document.createElement(tag.name);
     e._r = new RenderingScheduler(e, queue: queue);
     return e;
   }
 
   ViewFooterElement.created() : super.created() {
-    // TODO(cbernaschina) remove this when no more needed.
+    // TODO(cbernaschina) remove this when polymer is removed.
     _r = new RenderingScheduler(this);
   }
 
   @override
   void attached() {
     super.attached();
     _r.enable();
   }
 
   @override
   void detached() {
     super.detached();
+    children = [];
     _r.disable(notify: true);
-    children = [];
   }
 
   void render() {
     children = [
         new AnchorElement()
           ..href = 'https://www.dartlang.org/tools/observatory'
           ..text = 'View documentation',
         new AnchorElement()
           ..href = 'https://github.com/dart-lang/sdk/issues/new?title=Observatory:&amp;body=Observatory%20Feedback'
           ..text = 'File a bug report'
     ];
   }
 }