Make observable transform a barback transform.

pkg/source_maps/test/run.dart

 #!/usr/bin/env 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 test.run;
 
 import 'package:unittest/compact_vm_config.dart';
 import 'package:unittest/unittest.dart';
 import 'dart:io' show Options;
 
 import 'builder_test.dart' as builder_test;
 import 'end2end_test.dart' as end2end_test;
 import 'parser_test.dart' as parser_test;
 import 'printer_test.dart' as printer_test;
+import 'refactor_test.dart' as refactor_test;
 import 'span_test.dart' as span_test;
 import 'utils_test.dart' as utils_test;
 import 'vlq_test.dart' as vlq_test;
 
 main() {
   var args = new Options().arguments;
   var pattern = new RegExp(args.length > 0 ? args[0] : '.');
   useCompactVMConfiguration();
 
   void addGroup(testFile, testMain) {
     if (pattern.hasMatch(testFile)) {
       group(testFile.replaceAll('_test.dart', ':'), testMain);
     }
   }
 
   addGroup('builder_test.dart', builder_test.main);
   addGroup('end2end_test.dart', end2end_test.main);
   addGroup('parser_test.dart', parser_test.main);
   addGroup('printer_test.dart', printer_test.main);
+  addGroup('refactor_test.dart', refactor_test.main);
   addGroup('span_test.dart', span_test.main);
   addGroup('utils_test.dart', utils_test.main);
   addGroup('vlq_test.dart', vlq_test.main);
 }