Roll Observatory packages and add a roll script

packages/smoke/test/mirrors_used_test.dart

+// Copyright (c) 2014, 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 smoke.test.mirrors_test;
+
+import 'package:smoke/mirrors.dart';
+import 'package:unittest/unittest.dart';
+import 'common.dart' hide main;
+import 'common.dart' as common show main;
+
+@MirrorsUsed(
+    targets: const [A, B, C, D, E, E2, F, F2, G, H, L, L2, Type],
+    override: 'smoke.mirrors')
+import 'dart:mirrors';
+
+main() {
+  setUp(useMirrors);
+  common.main();
+}