Use native wrapper fields to store socket ids.

runtime/bin/stdio.dart

 // 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.
 
 const int _STDIO_HANDLE_TYPE_TERMINAL = 0;
 const int _STDIO_HANDLE_TYPE_PIPE = 1;
 const int _STDIO_HANDLE_TYPE_FILE = 2;
 const int _STDIO_HANDLE_TYPE_SOCKET = 3;
 const int _STDIO_HANDLE_TYPE_OTHER = -1;
 
 
 InputStream _stdin;
 OutputStream _stdout;
 OutputStream _stderr;
 
 
 InputStream _getStdioInputStream() {
   switch (_getStdioHandleType(0)) {
     case _STDIO_HANDLE_TYPE_TERMINAL:
     case _STDIO_HANDLE_TYPE_PIPE:
     case _STDIO_HANDLE_TYPE_SOCKET:
       Socket s = new _Socket._internalReadOnly();
       _getStdioHandle(s, 0);
+      s._closed = false;
       return s.inputStream;
     case _STDIO_HANDLE_TYPE_FILE:
       return new _FileInputStream.fromStdio(0);
     default:
       throw new FileIOException("Unsupported stdin type");
   }
 }
 
 
 OutputStream _getStdioOutputStream(int fd) {
   assert(fd == 1 || fd == 2);
   switch (_getStdioHandleType(fd)) {
     case _STDIO_HANDLE_TYPE_TERMINAL:
     case _STDIO_HANDLE_TYPE_PIPE:
     case _STDIO_HANDLE_TYPE_SOCKET:
       Socket s = new _Socket._internalWriteOnly();
       _getStdioHandle(s, fd);
+      s._closed = false;
       return s.outputStream;
     case _STDIO_HANDLE_TYPE_FILE:
       return new _FileOutputStream.fromStdio(fd);
     default:
       throw new FileIOException("Unsupported stdin type");
   }
 }
 
 
 InputStream get stdin {
@@ skipping 14 matching lines @@
 
 OutputStream get stderr {
   if (_stderr == null) {
     _stderr = _getStdioOutputStream(2);
   }
   return _stderr;
 }
 
 _getStdioHandle(Socket socket, int num) native "Socket_GetStdioHandle";
 _getStdioHandleType(int num) native "File_GetStdioHandleType";