Removed polymer & mirror from Observatory

runtime/observatory/lib/src/elements/error_ref.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.
 
 library error_ref_element;
 
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/models.dart'
   show ErrorRef;
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
 
 class ErrorRefElement extends HtmlElement implements Renderable {
-  static const tag = const Tag<ErrorRefElement>('error-ref-wrapped');
+  static const tag = const Tag<ErrorRefElement>('error-ref');
 
   RenderingScheduler<ErrorRefElement> _r;
 
   Stream<RenderedEvent<ErrorRefElement>> get onRendered => _r.onRendered;
 
   ErrorRef _error;
-  
+
   ErrorRef get error => _error;
 
   factory ErrorRefElement(ErrorRef error, {RenderingQueue queue}) {
     assert(error != null);
     ErrorRefElement e = document.createElement(tag.name);
     e._r = new RenderingScheduler<ErrorRefElement>(e, queue: queue);
     e._error = error;
     return e;
   }
 
@@ skipping 11 matching lines @@
     children = [];
     _r.disable(notify: true);
   }
 
   void render() {
     children = [
       new PreElement()..text = error.message
     ];
   }
 }