Add support of IP_MULTICAST_IF in UDP sockets.

content/browser/renderer_host/p2p/socket_host_udp_unittest.cc

Index: content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
diff --git a/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc b/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
index 5657f47ac993dc531c8ef4c96f80477d30896f8a..3ccacfc288985413d4b40a34bdc569a3fd426886 100644
--- a/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
+++ b/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
@@ -140,6 +140,11 @@ class FakeDatagramServerSocket : public net::DatagramServerSocket {
     return net::ERR_NOT_IMPLEMENTED;
   }
 
+  virtual int SetMulticastInterface(uint32 interface_index) OVERRIDE {
+    NOTIMPLEMENTED();
+    return net::ERR_NOT_IMPLEMENTED;
+  }
+
   virtual int SetMulticastTimeToLive(int time_to_live) OVERRIDE {
     NOTIMPLEMENTED();
     return net::ERR_NOT_IMPLEMENTED;