net: remove UsingTCPFastOpen() method from StreamSocket class

net/spdy/spdy_proxy_client_socket.cc

Index: net/spdy/spdy_proxy_client_socket.cc
diff --git a/net/spdy/spdy_proxy_client_socket.cc b/net/spdy/spdy_proxy_client_socket.cc
index 39ef8f0a7b1fad9aecb1bffb5c1365b86a8776d1..2d75c4cdc56a83847ce691920613f70e42a6d3e7 100644
--- a/net/spdy/spdy_proxy_client_socket.cc
+++ b/net/spdy/spdy_proxy_client_socket.cc
@@ -170,10 +170,6 @@ bool SpdyProxyClientSocket::WasEverUsed() const {
   return was_ever_used_ || (spdy_stream_.get() && spdy_stream_->WasEverUsed());
 }
 
-bool SpdyProxyClientSocket::UsingTCPFastOpen() const {
-  return false;
-}
-
 bool SpdyProxyClientSocket::WasNpnNegotiated() const {
   return false;
 }