Add utility methods for sending non-form data in pkg/http.

pkg/http/test/utils.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.
 
 library test_utils;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 55 matching lines @@
         }
 
         response.headers.contentType =
             new ContentType(
                 "application", "json", charset: outputEncoding.name);
         response.headers.set('single', 'value');
 
         var requestBody;
         if (requestBodyBytes.isEmpty) {
           requestBody = null;
-        } else if (request.headers.contentType.charset != null) {
+        } else if (request.headers.contentType != null &&
+            request.headers.contentType.charset != null) {
           var encoding = requiredEncodingForCharset(
               request.headers.contentType.charset);
           requestBody = encoding.decode(requestBodyBytes);
         } else {
           requestBody = requestBodyBytes;
         }
 
         var content = {
           'method': request.method,
           'path': request.uri.path,
@@ skipping 112 matching lines @@
 const isSocketException = const _SocketException();
 
 /// A matcher for functions that throw SocketException.
 const Matcher throwsSocketException =
     const Throws(isSocketException);
 
 class _SocketException extends TypeMatcher {
   const _SocketException() : super("SocketException");
   bool matches(item, Map matchState) => item is SocketException;
 }