Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/args/src/utils.dart

Index: observatory_pub_packages/args/src/utils.dart
===================================================================
--- observatory_pub_packages/args/src/utils.dart	(revision 0)
+++ observatory_pub_packages/args/src/utils.dart	(working copy)
@@ -0,0 +1,9 @@
+// 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 args.utils;
+
+/// Pads [source] to [length] by adding spaces at the end.
+String padRight(String source, int length) =>
+    source + ' ' * (length - source.length);