Split dart:builtin into dart:builtin and dart:io.

samples/chat/chat_server_lib.dart

Index: samples/chat/chat_server_lib.dart
diff --git a/samples/chat/chat_server_lib.dart b/samples/chat/chat_server_lib.dart
index 97242aa73dc1dc2ade52a55cb4774529399f1707..0ed29cd5c9f3eea8a68cc763cd61d645b0946a5b 100644
--- a/samples/chat/chat_server_lib.dart
+++ b/samples/chat/chat_server_lib.dart
@@ -1,8 +1,9 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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("chat_server");
+#import("dart:io");
 #import("http.dart");
 #import("../../client/json/dart_json.dart");