Roll Observatory packages and add a roll script

initialize/lib/src/init_method.dart

-// 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.
-part of initialize;
-
-/// Metadata used to label static or top-level methods that are called
-/// automatically when calling static_init.run(). This class is private because
-/// it shouldn't be used directly in annotations, instead use the `initMethod`
-/// singleton below.
-typedef dynamic _ZeroArg();
-class _InitMethod implements Initializer<_ZeroArg> {
-  const _InitMethod();
-
-  @override
-  initialize(_ZeroArg method) => method();
-}
-
-/// We only ever need one instance of the `_InitMethod` class, this is it.
-const initMethod = const _InitMethod();