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

webrtc/base/socketserver.h

Index: webrtc/base/socketserver.h
diff --git a/webrtc/base/socketserver.h b/webrtc/base/socketserver.h
index 15c56f4612798e5c2bcba3972d664ce774c84cde..073cc996f6bbd50e651e0ef5896e7948d1f5b8c2 100644
--- a/webrtc/base/socketserver.h
+++ b/webrtc/base/socketserver.h
@@ -39,6 +39,9 @@ class SocketServer : public SocketFactory {
 
   // Causes the current wait (if one is in progress) to wake up.
   virtual void WakeUp() = 0;
+
+  // A network binder will bind the created sockets to a network.
+  virtual void MaybeSetNetworkBinder() {}
 };
 
 }  // namespace rtc