Currently we have access to nsNSSSocketInfo that implements TransportSecurityInfo. When we move netwirking to the socket process nsNSSSocketInfo moves as well. We will need a clone of TransportSecurityInfo on the parent process. There is already a way to serialize/deserialize TransportSecurityInfo here.
Also we will need some info from nsISSLSocketControl. As far as
I can see we only need NegotiatedNPN (here) but we should double check.