Add support of IP_MULTICAST_IF in UDP sockets.

net/udp/udp_socket_unittest.cc

 // 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/udp/udp_client_socket.h"
 #include "net/udp/udp_server_socket.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
@@ skipping 556 matching lines @@
   UDPSocket socket(DatagramSocket::DEFAULT_BIND,
                    RandIntCallback(),
                    NULL,
                    NetLog::Source());
   // Before binding.
   EXPECT_EQ(OK, socket.SetMulticastLoopbackMode(false));
   EXPECT_EQ(OK, socket.SetMulticastLoopbackMode(true));
   EXPECT_EQ(OK, socket.SetMulticastTimeToLive(0));
   EXPECT_EQ(OK, socket.SetMulticastTimeToLive(3));
   EXPECT_NE(OK, socket.SetMulticastTimeToLive(-1));
+  EXPECT_EQ(OK, socket.SetMulticastInterface(0));
 
   EXPECT_EQ(OK, socket.Bind(bind_address));
 
+  EXPECT_NE(OK, socket.SetMulticastLoopbackMode(false));
+  EXPECT_NE(OK, socket.SetMulticastTimeToLive(0));
+  EXPECT_NE(OK, socket.SetMulticastInterface(0));
+
   socket.Close();
 }
 
 }  // namespace
 
 }  // namespace net