Bind a socket to a network if the network handle is set.

webrtc/p2p/base/basicpacketsocketfactory.cc

Index: webrtc/p2p/base/basicpacketsocketfactory.cc
diff --git a/webrtc/p2p/base/basicpacketsocketfactory.cc b/webrtc/p2p/base/basicpacketsocketfactory.cc
index 697518da9d0508cfcec888306b133514307726c7..a6aa3105b98fe8b0185feeb0c7864441b2fa52cc 100644
--- a/webrtc/p2p/base/basicpacketsocketfactory.cc
+++ b/webrtc/p2p/base/basicpacketsocketfactory.cc
@@ -27,11 +27,13 @@ namespace rtc {
 BasicPacketSocketFactory::BasicPacketSocketFactory()
     : thread_(Thread::Current()),
       socket_factory_(NULL) {
+  thread_->socketserver()->MaybeSetNetworkBinder();
 }
 
 BasicPacketSocketFactory::BasicPacketSocketFactory(Thread* thread)
     : thread_(thread),
       socket_factory_(NULL) {
+  thread_->socketserver()->MaybeSetNetworkBinder();
 }
 
 BasicPacketSocketFactory::BasicPacketSocketFactory(