Add missing files.

sdk/lib/io/service_object.dart

Index: sdk/lib/io/service_object.dart
diff --git a/sdk/lib/io/service_object.dart b/sdk/lib/io/service_object.dart
new file mode 100644
index 0000000000000000000000000000000000000000..43bd6512b5fe395371fc17f427d3a7062f599ba6
--- /dev/null
+++ b/sdk/lib/io/service_object.dart
@@ -0,0 +1,29 @@
+// 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.
+
+part of dart.io;
+
+int _nextServiceId = 1;
+
+// TODO(ajohnsen): Use other way of getting a uniq id.
+abstract class _ServiceObject {
+  int __serviceId = 0;
+  int get _serviceId {
+    if (__serviceId == 0) __serviceId = _nextServiceId++;
+    return __serviceId;
+  }
+
+  Map _toJSON(bool ref);
+
+  String get _servicePath => "$_serviceTypePath/$_serviceId";
+
+  String get _serviceTypePath;
+
+  String get _serviceTypeName;
+
+  String _serviceType(bool ref) {
+    if (ref) return "@$_serviceTypeName";
+    return _serviceTypeName;
+  }
+}