Centralized event streams

runtime/observatory/lib/src/elements/script_ref.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 script_ref_element;
 
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/models.dart' as M show IsolateRef, ScriptRef;
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
@@ skipping 23 matching lines @@
     e._isolate = isolate;
     e._script = script;
     return e;
   }
 
   ScriptRefElement.created() : super.created();
 
   @override
   void attached() {
     super.attached();
-    assert(script != null);
     _r.enable();
   }
 
   @override
   void detached() {
     super.detached();
     children = [];
     _r.disable(notify: true);
   }
 
   void render() {
     children = [
       new AnchorElement(href: Uris.inspect(isolate, object: script))
         ..title = script.uri
         ..text = script.uri.split('/').last
     ];
   }
 }