Remove public SocketInputStream and SocketOutputStream clases

runtime/bin/socket_stream.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.
-
-/**
- * [SocketInputStream] makes it possible to stream over data received
- * from a [Socket].
- */
-abstract class SocketInputStream implements InputStream {
-  /**
-   * Create a [SocketInputStream] for streaming from a [Socket].
-   */
-  factory SocketInputStream(Socket socket) => new _SocketInputStream(socket);
-}
-
-/**
- * [SocketOutputStream] makes it possible to stream data to a
- * [Socket].
- */
-abstract class SocketOutputStream implements OutputStream {
-  /**
-   * Create a [SocketOutputStream] for streaming to a [Socket].
-   */
-  factory SocketOutputStream(Socket socket) => new _SocketOutputStream(socket);
-}