Roll Observatory packages and add a roll script

packages/web_components/test/deps/b.dart

Index: packages/web_components/test/deps/b.dart
diff --git a/web_components/lib/init.dart b/packages/web_components/test/deps/b.dart
similarity index 65%
copy from web_components/lib/init.dart
copy to packages/web_components/test/deps/b.dart
index 1ebb1413f9023f4113e1c1616511af98477037f5..63b8dfae49d1d7bd5511697a88cfaa82a076ddbc 100644
--- a/web_components/lib/init.dart
+++ b/packages/web_components/test/deps/b.dart
@@ -1,9 +1,7 @@
 // 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.
-library web_components.init;
+@initializeTracker
+library web_components.test.deps.b;
 
-import 'dart:async';
-import 'src/init.dart';
-
-Future main() => initWebComponents();
+import 'package:initialize/src/initialize_tracker.dart';