Removed Polymer from Observatory deps

packages/web_components/test/location_wrapper_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.
 
+@TestOn('browser')
 library template_wrappers_test;
 
 import 'dart:html';
-import 'package:unittest/html_config.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 main() {
-  useHtmlConfiguration();
-
   test('OK to access location with platform.js', () {
     expect(window.location.toString(), window.location.href);
   });
 }