Update polymer to commit b7200854b2441a22ce89f6563963f36c50f5150d

pkg/polymer/test/prop_attr_bind_reflection_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.
 
-import 'dart:async' show Completer;
 import 'dart:html';
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'package:polymer/polymer.dart';
 
 @CustomTag('my-child-element')
 class MyChildElement extends PolymerElement {
   @published int camelCase;
   @published int lowercase;
 
@@ skipping 19 matching lines @@
 
   test('attribute reflected to property name', () {
     var child = query('my-element').shadowRoot.query('my-child-element');
     expect(child.lowercase, 11);
     expect(child.camelCase, 11);
 
     expect('11', child.attributes['lowercase']);
     expect('11', child.attributes['camelcase']);
   });
 }