Fix HttpBodyHandler to handle missing mimeType.

sdk/lib/io/http.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;
 
 /**
  * HTTP status codes.
  */
 abstract class HttpStatus {
@@ skipping 491 matching lines @@
    *     text/html; charset=utf-8
    *
    * will create a content type object with primary type [:text:], sub
    * type [:html:] and parameter [:charset:] with value [:utf-8:].
    */
   factory ContentType.fromString(String value) {
     return new _ContentType.fromString(value);
   }
 
   /**
+   * Gets the mime-type, without any parameters.
+   */
+  String get mimeType;
+
+  /**
    * Gets the primary type.
    */
   String get primaryType;
 
   /**
    * Gets the sub type.
    */
   String get subType;
 
   /**
@@ skipping 776 matching lines @@
 class RedirectLimitExceededException extends RedirectException {
   const RedirectLimitExceededException(List<RedirectInfo> redirects)
       : super("Redirect limit exceeded", redirects);
 }
 
 
 class RedirectLoopException extends RedirectException {
   const RedirectLoopException(List<RedirectInfo> redirects)
       : super("Redirect loop detected", redirects);
 }