Use dartfmt on Observatory code

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/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');
 
   RenderingScheduler<ErrorRefElement> _r;
 
   Stream<RenderedEvent<ErrorRefElement>> get onRendered => _r.onRendered;
 
@@ skipping 18 matching lines @@
   }
 
   @override
   void detached() {
     super.detached();
     children = [];
     _r.disable(notify: true);
   }
 
   void render() {
-    children = [
-      new PreElement()..text = error.message
-    ];
+    children = [new PreElement()..text = error.message];
   }
 }