Plumbing for TCP FastOpen for SSL sockets.

net/socket/tcp_socket_libevent.h

Index: net/socket/tcp_socket_libevent.h
diff --git a/net/socket/tcp_socket_libevent.h b/net/socket/tcp_socket_libevent.h
index 0335c9ea2dea0587ad6ff29421f3a2b3176363dd..45eb115394e1598757e1012ace49c6d744795faa 100644
--- a/net/socket/tcp_socket_libevent.h
+++ b/net/socket/tcp_socket_libevent.h
@@ -21,6 +21,11 @@ class IOBuffer;
 class IPEndPoint;
 class SocketLibevent;
 
+// Checks if TCP FastOpen is supported by the kernel. Also enables TFO for all
+// connections if indicated by user.
+// Not thread safe.  Must be called during initialization/startup only.
+NET_EXPORT void CheckSupportAndMaybeEnableTCPFastOpen(bool user_enabled);
+
 class NET_EXPORT TCPSocketLibevent {
  public:
   TCPSocketLibevent(NetLog* net_log, const NetLog::Source& source);
@@ -65,7 +70,10 @@ class NET_EXPORT TCPSocketLibevent {
 
   void Close();
 
+  // Setter/Getter methods for TCP FastOpen socket option.
   bool UsingTCPFastOpen() const;
+  void EnableTCPFastOpen();
+
   bool IsValid() const;
 
   // Marks the start/end of a series of connect attempts for logging purpose.
@@ -168,11 +176,10 @@ class NET_EXPORT TCPSocketLibevent {
   scoped_ptr<SocketLibevent> accept_socket_;
 
   // Enables experimental TCP FastOpen option.
-  const bool use_tcp_fastopen_;
+  bool use_tcp_fastopen_if_supported_;
 
   // True when TCP FastOpen is in use and we have done the connect.
   bool tcp_fastopen_connected_;
-
   FastOpenStatus fast_open_status_;
 
   bool logging_multiple_connect_attempts_;