use shared code transformer, update web_components to remove .map and .concat files

pkg/polymer/test/build/remove_sourcemap_comment_test.dart

Index: pkg/polymer/test/build/remove_sourcemap_comment_test.dart
diff --git a/pkg/polymer/test/build/remove_sourcemap_comment_test.dart b/pkg/polymer/test/build/remove_sourcemap_comment_test.dart
deleted file mode 100644
index 44d1f455b4d7e3142379669bebcdddef0c8f7b79..0000000000000000000000000000000000000000
--- a/pkg/polymer/test/build/remove_sourcemap_comment_test.dart
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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 polymer.test.build.remove_sourcemap_comment_test;
-
-import 'package:barback/barback.dart';
-import 'package:polymer/src/build/remove_sourcemap_comment.dart';
-import 'package:unittest/compact_vm_config.dart';
-import 'package:unittest/unittest.dart';
-import 'common.dart';
-
-final phases = [[new RemoveSourcemapComment.asPlugin(
-    new BarbackSettings({}, BarbackMode.RELEASE))]];
-
-void main() {
-  useCompactVMConfiguration();
-
-  testPhases('removes sourcemap comments', phases, {
-      'a|web/test.js': '''
-          var i = 0;
-          //# sourceMappingURL=*.map''',
-  }, {
-      'a|web/test.js': '''
-          var i = 0;''',
-  });
-}