Add experimental option for TCP FastOpen....

net/socket/socks5_client_socket.cc

Index: net/socket/socks5_client_socket.cc
===================================================================
--- net/socket/socks5_client_socket.cc	(revision 63182)
+++ net/socket/socks5_client_socket.cc	(working copy)
@@ -130,6 +130,14 @@
   return false;
 }
 
+bool SOCKS5ClientSocket::UsingTCPFastOpen() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->UsingTCPFastOpen();
+  }
+  NOTREACHED();
+  return false;
+}
+
 // Read is called by the transport layer above to read. This can only be done
 // if the SOCKS handshake is complete.
 int SOCKS5ClientSocket::Read(IOBuffer* buf, int buf_len,