unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/lib/io/service_object.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.
-
-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;
-  }
-}