Add DefaultListenSocket.

net/base/listen_socket.cc

Index: net/base/listen_socket.cc
diff --git a/net/base/listen_socket.cc b/net/base/listen_socket.cc
new file mode 100644
index 0000000000000000000000000000000000000000..72ba2e376f8891788f394b890b48d01cf5e7da51
--- /dev/null
+++ b/net/base/listen_socket.cc
@@ -0,0 +1,13 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/base/listen_socket.h"
+
+namespace net {
+
+ListenSocket::ListenSocket(ListenSocketDelegate* del) : socket_delegate_(del) {}
+
+ListenSocket::~ListenSocket() {}
+
+}  // namespace net