Removed Polymer from Observatory deps

packages/web_components/test/build/mirrors_remover_test.dart

 // Copyright (c) 2015, 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('vm')
 library web_components.test.build.mirrors_remover_test;
 
-import 'package:code_transformers/tests.dart';
+import 'package:transformer_test/utils.dart';
 import 'package:web_components/build/mirrors_remover.dart';
-import 'package:unittest/compact_vm_config.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 main() {
-  useCompactVMConfiguration();
-
   var transformer = new MirrorsRemoverTransformer();
-  var phases = [[transformer]];
+  var phases = [
+    [transformer]
+  ];
 
   testPhases('basic', phases, {
     'a|lib/src/init.dart': '''
         libary web_components.init;
 
         import 'src/mirror_initializer.dart' as init;
         export 'src/mirror_initializer.dart' show deployMode;
 
         foo() {}
         ''',
   }, {
     'a|lib/src/init.dart': '''
         libary web_components.init;
 
         import 'src/static_initializer.dart' as init;
         export 'src/static_initializer.dart' show deployMode;
 
         foo() {}
         ''',
-  }, []);
+  }, messages: []);
 }