Improve web-socket implementation by using making _WebSocketProtocolProcessor a StreamTransformer.

tests/standalone/io/web_socket_test.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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 import "dart:async";
@@ skipping 103 matching lines @@
         webSocket.send(messageText);
       });
 
       for (int i = 0; i < totalConnections; i++) {
         createClient(server.port).then((webSocket) {
             webSocket.listen(
                 webSocket.send,
                 onDone: () {
                   Expect.equals(closeStatus == null
                                 ? WebSocketStatus.NO_STATUS_RECEIVED
-                                : closeStatus, event.code);
-                  Expect.equals(
-                      closeReason == null ? "" : closeReason, event.reason);
+                                : closeStatus, webSocket.closeCode);
+                  Expect.equals(closeReason == null
+                                ? ""
+                                : closeReason, webSocket.closeReason);
                 });
             });
       }
     });
   }
 
 
   void testMessageLength(int messageLength) {
     createServer().then((server) {
       Uint8List originalMessage = new Uint8List(messageLength);
@@ skipping 130 matching lines @@
                 Expect.isTrue(onopenCalled);
                 Expect.isFalse(oncloseCalled);
                 Expect.equals(WebSocket.OPEN, webSocket.readyState);
                 webSocket.send(message);
               },
               onDone: () {
                 Expect.isTrue(onopenCalled);
                 Expect.equals(10, onmessageCalled);
                 Expect.isFalse(oncloseCalled);
                 oncloseCalled = true;
-                Expect.isTrue(event.wasClean);
-                Expect.equals(3002, event.code);
-                Expect.equals("Got tired", event.reason);
+                Expect.equals(3002, webSocket.closeCode);
+                Expect.equals("Got tired", webSocket.closeReason);
                 Expect.equals(WebSocket.CLOSED, webSocket.readyState);
               });
         });
       }
 
       for (int i = 0; i < totalConnections; i++) {
         webSocketConnection();
       }
     });
   }
@@ skipping 73 matching lines @@
   SecureSocket.initialize(database: testPkcertDatabase.toNativePath(),
                           password: "dartdart");
 }
 
 
 main() {
   new SecurityConfiguration(secure: false).runTests();
   initializeSSL();
   new SecurityConfiguration(secure: true).runTests();
 }