Converted Observatory cpu-profile element

runtime/observatory/tests/observatory_ui/class_tree/element_test.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.
+
 import 'dart:html';
 import 'package:unittest/unittest.dart';
 import 'package:observatory/src/elements/class_tree.dart';
 import 'package:observatory/src/elements/nav/notify.dart';
 import '../mocks.dart';
 
 main() {
   ClassTreeElement.tag.ensureRegistration();
 
   final nTag = NavNotifyElement.tag.name;
@@ skipping 41 matching lines @@
       await e.onRendered.first;
       rendered = true;
       expect(e.children.length, isNonZero, reason: 'has elements');
       expect(e.querySelectorAll(nTag).length, equals(1));
       e.remove();
       await e.onRendered.first;
       expect(e.children.length, isZero, reason: 'is empty');
     });
   });
 }