Roll Observatory packages and add a roll script

packages/polymer/test/when_polymer_ready_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.
+
+library polymer.test.when_polymer_ready_test;
+
+import 'dart:async';
+import 'dart:html';
+
+import 'package:polymer/polymer.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+final Completer done = new Completer();
+
+@CustomTag('x-a')
+class XA extends PolymerElement {
+  XA.created() : super.created();
+}
+
+main() {
+  useHtmlConfiguration();
+
+  test('whenPolymerReady functions get called when polymer is ready', () {
+    expect(querySelector('x-a') is XA, isFalse);
+    initPolymer();
+    return done.future;
+  });
+}
+
+@whenPolymerReady
+void whenReady() {
+  expect(querySelector('x-a') is XA, isTrue);
+  done.complete();
+}