Allow an empty HTTP resason phrase

sdk/lib/io/http_parser.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;
 
 // Global constants.
 class _Const {
   // Bytes for "HTTP".
   static const HTTP = const [72, 84, 84, 80];
@@ skipping 402 matching lines @@
               if (byte < 0x30 && 0x39 < byte) {
                 throw new HttpParserException("Invalid response status code");
               } else {
                 _method_or_status_code.add(byte);
               }
             }
             break;
 
           case _State.RESPONSE_LINE_REASON_PHRASE:
             if (byte == _CharCode.CR) {
-              if (_uri_or_reason_phrase.length == 0) {
-                throw new HttpParserException("Invalid response reason phrase");
-              }
               _state = _State.RESPONSE_LINE_ENDING;
             } else {
               if (byte == _CharCode.CR || byte == _CharCode.LF) {
                 throw new HttpParserException("Invalid response reason phrase");
               }
               _uri_or_reason_phrase.add(byte);
             }
             break;
 
           case _State.RESPONSE_LINE_ENDING:
@@ skipping 538 matching lines @@
   StreamController<_HttpIncoming> _controller;
   StreamController<List<int>> _bodyController;
 }
 
 
 class HttpParserException implements Exception {
   const HttpParserException([String this.message = ""]);
   String toString() => "HttpParserException: $message";
   final String message;
 }