net: remove UsingTCPFastOpen() method from StreamSocket class

jingle/glue/proxy_resolving_client_socket.cc

Index: jingle/glue/proxy_resolving_client_socket.cc
diff --git a/jingle/glue/proxy_resolving_client_socket.cc b/jingle/glue/proxy_resolving_client_socket.cc
index 731b63c43436c705dff707eb34b2ffdaf7fa2aa5..19623197f51e09e74ae6f1b0ce20f328bda2fc23 100644
--- a/jingle/glue/proxy_resolving_client_socket.cc
+++ b/jingle/glue/proxy_resolving_client_socket.cc
@@ -400,13 +400,6 @@ bool ProxyResolvingClientSocket::WasEverUsed() const {
   return false;
 }
 
-bool ProxyResolvingClientSocket::UsingTCPFastOpen() const {
-  if (transport_.get() && transport_->socket())
-    return transport_->socket()->UsingTCPFastOpen();
-  NOTREACHED();
-  return false;
-}
-
 bool ProxyResolvingClientSocket::WasNpnNegotiated() const {
   return false;
 }