Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/collection/src/utils.dart

Index: observatory_pub_packages/collection/src/utils.dart
===================================================================
--- observatory_pub_packages/collection/src/utils.dart	(revision 0)
+++ observatory_pub_packages/collection/src/utils.dart	(working copy)
@@ -0,0 +1,13 @@
+// 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 dart.pkg.collection.utils;
+
+/// A pair of values.
+class Pair<E, F> {
+  E first;
+  F last;
+
+  Pair(this.first, this.last);
+}