Fix Observatory code coverage

runtime/bin/vmservice/client/lib/src/elements/script_view.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_view_element;
 
 import 'observatory_element.dart';
 import 'package:observatory/elements.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
 /// Displays an Script response.
 @CustomTag('script-view')
 class ScriptViewElement extends ObservatoryElement {
   @published Script script;
-  @published bool showCoverage = false;
 
   ScriptViewElement.created() : super.created();
 
   @override
   void attached() {
     super.attached();
     if (script == null) {
       return;
     }
     script.load();
   }
 
-  showCoverageChanged(oldValue) {
-    ScriptInsetElement sie = shadowRoot.querySelector('#scriptInset');
-    sie.coverage = showCoverage;
-  }
-
   void refresh(var done) {
     script.reload().whenComplete(done);
   }
 
   void refreshCoverage(var done) {
-    script.isolate.refreshCoverage().then((_) {
-      ScriptInsetElement sie = shadowRoot.querySelector('#scriptInset');
-      showCoverage = true;
-      sie.coverage = showCoverage;
-    }).whenComplete(done);
+    script.isolate.refreshCoverage()..whenComplete(done);
   }
 }