Fix web_socket_protocol_processor_test to pass in checked mode.

tests/standalone/io/web_socket_protocol_processor_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.
 
 import "dart:utf";
 import "dart:math";
 import "dart:async";
 import "dart:collection";
 import "dart:scalarlist";
 
@@ skipping 12 matching lines @@
 // collect the message and expect it to be equal to the
 // expectedMessage field when fully received.
 class WebSocketMessageCollector {
   List<int> expectedMessage;
 
   int messageCount = 0;
   int closeCount = 0;
 
   var data;
 
-  WebSocketMessageCollector(_WebSocketProtocolTransformer transformer,
+  WebSocketMessageCollector(Stream stream,
                             [List<int> this.expectedMessage = null]) {
-    transformer.listen(onMessageData, onDone: onClosed, onError: onError);
+    stream.listen(onMessageData, onDone: onClosed, onError: onError);
   }
 
   void onMessageData(buffer) {
     if (buffer is String) {
       buffer = _encodeString(buffer);
     }
     Expect.listEquals(expectedMessage, buffer);
     messageCount++;
     data = buffer;
   }
 
-  void onClosed(int status, String reason) {
+  void onClosed() {
     closeCount++;
   }
 
   void onError(e) {
     Expect.fail("Unexpected error $e");
   }
 
 }
 
 
@@ skipping 164 matching lines @@
   runTest(65534, 65537, 1);
   print("Fragment messages test, messages $messageCount, frames $frameCount");
   Expect.equals(messageCount, mc.messageCount);
   Expect.equals(0, mc.closeCount);
 }
 
 void main() {
   testFullMessages();
   testFragmentedMessages();
 }