added bool type to named args in lib/io and lib/_internal

sdk/lib/io/http_impl.dart

 // Copyright (c) 2013, 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;
 
 class _HttpIncoming extends Stream<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
@@ skipping 456 matching lines @@
   Future<T> addStream(Stream<List<int>> stream) {
     return _dataSink.addStream(stream);
   }
 
   Future close() {
     return _dataSink.close();
   }
 
   Future<T> get done => _dataSink.done;
 
-  Future _writeHeaders({drainRequest: true}) {
+  Future _writeHeaders({bool drainRequest: true}) {
     if (_headersWritten) return new Future.value();
     _headersWritten = true;
     headers._synchronize();  // Be sure the 'chunked' option is updated.
     _dataSink.encoding = encoding;
     bool isServerSide = this is _HttpResponse;
     if (isServerSide) {
       var response = this;
       if (headers.chunkedTransferEncoding) {
         List acceptEncodings =
             response._httpRequest.headers[HttpHeaders.ACCEPT_ENCODING];
@@ skipping 1982 matching lines @@
   final Uri location;
 }
 
 String _getHttpVersion() {
   var version = Platform.version;
   // Only include major and minor version numbers.
   int index = version.indexOf('.', version.indexOf('.') + 1);
   version = version.substring(0, index);
   return 'Dart/$version (dart:io)';
 }