Add support of IP_MULTICAST_IF in UDP sockets.

net/dns/mock_mdns_socket_factory.h

Index: net/dns/mock_mdns_socket_factory.h
diff --git a/net/dns/mock_mdns_socket_factory.h b/net/dns/mock_mdns_socket_factory.h
index 4d1c19093e6e2ffc5a8ca196040f8e19623f2c29..1608658d0a2a84d1f448c7df1326bb6c1527208b 100644
--- a/net/dns/mock_mdns_socket_factory.h
+++ b/net/dns/mock_mdns_socket_factory.h
@@ -45,12 +45,10 @@ class MockMDnsDatagramServerSocket : public DatagramServerSocket {
   MOCK_METHOD0(AllowAddressReuse, void());
   MOCK_METHOD0(AllowBroadcast, void());
 
-  MOCK_CONST_METHOD1(JoinGroup, int(const IPAddressNumber& group_address));
-
-  MOCK_CONST_METHOD1(LeaveGroup, int(const IPAddressNumber& address));
-
+  MOCK_METHOD1(SetMulticastInterface, int(uint32 interface_index));
+  MOCK_METHOD1(JoinGroup, int(const IPAddressNumber& group_address));
+  MOCK_METHOD1(LeaveGroup, int(const IPAddressNumber& address));
   MOCK_METHOD1(SetMulticastTimeToLive, int(int ttl));
-
   MOCK_METHOD1(SetMulticastLoopbackMode, int(bool loopback));
 
   MOCK_METHOD1(SetDiffServCodePoint, int(DiffServCodePoint dscp));