Fix URL decoding in HTTP library

tests/standalone/io/http_date_test.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.
 
+#source("../../../runtime/bin/input_stream.dart");
+#source("../../../runtime/bin/output_stream.dart");
+#source("../../../runtime/bin/chunked_stream.dart");
+#source("../../../runtime/bin/string_stream.dart");
+#source("../../../runtime/bin/stream_util.dart");
+#source("../../../runtime/bin/http.dart");
+#source("../../../runtime/bin/http_impl.dart");
+#source("../../../runtime/bin/http_parser.dart");
 #source("../../../runtime/bin/http_utils.dart");
 
-class HttpException implements Exception {
-  const HttpException([String this.message = ""]);
-  String toString() => "HttpException: $message";
-  final String message;
-}
-
 void testParseHttpDate() {
   TimeZone utc = new TimeZone.utc();
   Date date;
   date = new Date.withTimeZone(1999, Date.JUN, 11, 18, 46, 53, 0, utc);
   Expect.equals(date, _HttpUtils.parseDate("Fri, 11 Jun 1999 18:46:53 GMT"));
   Expect.equals(date, _HttpUtils.parseDate("Friday, 11-Jun-1999 18:46:53 GMT"));
   Expect.equals(date, _HttpUtils.parseDate("Fri Jun 11 18:46:53 1999"));
 
   date = new Date.withTimeZone(1970, Date.JAN, 1, 0, 0, 0, 0, utc);
   Expect.equals(date, _HttpUtils.parseDate("Thu, 1 Jan 1970 00:00:00 GMT"));
@@ skipping 59 matching lines @@
   Expect.throws(() {
     _HttpUtils.parseDate("$valid ");
   });
 }
 
 void main() {
   testParseHttpDate();
   testFormatParseHttpDate();
   testParseHttpDateFailures();
 }