Validate headers when added to HttpHeaders.

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 894 matching lines @@
     _remainingContent = -1;
 
     _headers = null;
   }
 
   void _releaseBuffer() {
     _buffer = null;
     _index = null;
   }
 
-  bool _isTokenChar(int byte) {
+  static bool _isTokenChar(int byte) {
     return byte > 31 && byte < 128 && !_Const.SEPARATOR_MAP[byte];
   }
 
+  static bool _isValueChar(int byte) {
+    return (byte > 31 && byte < 128) || (byte == _CharCode.SP) ||
+        (byte == _CharCode.HT);
+  }
+
   static List<String> _tokenizeFieldValue(String headerValue) {
     List<String> tokens = new List<String>();
     int start = 0;
     int index = 0;
     while (index < headerValue.length) {
       if (headerValue[index] == ",") {
         tokens.add(headerValue.substring(start, index));
         start = index + 1;
       } else if (headerValue[index] == " " || headerValue[index] == "\t") {
         start++;
@@ skipping 105 matching lines @@
     }
   }
 
   void _reportError(error, [stackTrace]) {
     if (_socketSubscription != null) _socketSubscription.cancel();
     _state = _State.FAILURE;
     _controller.addError(error, stackTrace);
     _controller.close();
   }
 }