pkg: analysis aided cleanup

pkg/mdv/test/custom_element_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 custom_element_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';
 
 main() {
   mdv.initialize();
   useHtmlConfiguration();
   group('Custom Element Bindings', customElementBindingsTest);
 }
 
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   }
 
   void clear() => _map.clear();
   void forEach(void f(K key, V value)) => _map.forEach(f);
   Iterable<K> get keys => _map.keys;
   Iterable<V> get values => _map.values;
   int get length => _map.length;
   bool get isEmpty => _map.isEmpty;
   bool get isNotEmpty => _map.isNotEmpty;
 }