Remove public SocketInputStream and SocketOutputStream clases

tests/standalone/io/echo_server_stream_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.
 //
 // Echo server test program to test socket streams.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
@@ skipping 21 matching lines @@
   }
 
   void sendData() {
 
     void errorHandler(Exception e) {
       Expect.fail("Socket error $e");
     }
 
     void connectHandler() {
 
-      SocketOutputStream stream = _socket.outputStream;
+      OutputStream stream = _socket.outputStream;
 
       void dataSent() {
         InputStream inputStream = _socket.inputStream;
         int offset = 0;
         List<int> data;
 
         void onClosed() {
           Expect.equals(MSGSIZE, offset);
           _messages++;
           if (_messages < MESSAGES) {
@@ skipping 89 matching lines @@
 class EchoServer extends TestingServer {
 
   static const int MSGSIZE = EchoServerGame.MSGSIZE;
 
   void onConnection(Socket connection) {
     InputStream inputStream;
     List<int> buffer = new List<int>(MSGSIZE);
     int offset = 0;
 
     void dataReceived() {
-      SocketOutputStream outputStream;
       int bytesRead;
-      outputStream = connection.outputStream;
+      OutputStream outputStream = connection.outputStream;
       bytesRead = inputStream.readInto(buffer, offset, MSGSIZE - offset);
       if (bytesRead > 0) {
         offset += bytesRead;
         for (int i = 0; i < offset; i++) {
           Expect.equals(EchoServerGame.FIRSTCHAR + i, buffer[i]);
         }
         if (offset == MSGSIZE) {
           outputStream.write(buffer);
           outputStream.close();
         }
       }
     }
 
     void errorHandler(Exception e) {
       Expect.fail("Socket error $e");
     }
 
     inputStream = connection.inputStream;
     inputStream.onData = dataReceived;
     connection.onError = errorHandler;
   }
 }
 
 main() {
   EchoServerGame echoServerGame = new EchoServerGame.start();
 }