pkg: analysis aided cleanup

pkg/mdv/test/node_bindings_test.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 node_bindings_test;
 
-import 'dart:async';
 import 'dart:html';
 import 'package:mdv/mdv.dart' as mdv;
-import 'package:observe/observe.dart';
 import 'package:unittest/html_config.dart';
 import 'package:unittest/unittest.dart';
 import 'mdv_test_utils.dart';
 
 // Note: this file ported from
 // https://github.com/toolkitchen/mdv/blob/master/tests/node_bindings.js
 
 main() {
   mdv.initialize();
   useHtmlConfiguration();
@@ skipping 128 matching lines @@
     expect(input.checked, false);
 
     input.click();
     expect(model[sym('x')], true);
     performMicrotaskCheckpoint();
 
     input.click();
     expect(model[sym('x')], false);
   });
 }