Implement Token Binding negotiation TLS extension

net/socket/ssl_client_socket_openssl.h

Index: net/socket/ssl_client_socket_openssl.h
diff --git a/net/socket/ssl_client_socket_openssl.h b/net/socket/ssl_client_socket_openssl.h
index dbceeafa3fc5dbe0dc4f9ae8c4f348dfacd09220..a41848d802a34d7fdeb6aa88d28395bdeb2c591e 100644
--- a/net/socket/ssl_client_socket_openssl.h
+++ b/net/socket/ssl_client_socket_openssl.h
@@ -210,6 +210,32 @@ class SSLClientSocketOpenSSL : public SSLClientSocket {
   void OnPrivateKeySignComplete(Error error,
                                 const std::vector<uint8_t>& signature);
 
+  // Token Binding Extension callbacks. The Add and Parse callbacks are wrappers
+  // around the instance methods.
+  static int TokenBindingAddCallback(SSL* ssl,
+                                     unsigned int extension_value,
+                                     const uint8_t** out,
+                                     size_t* out_len,
+                                     int* out_alert_value,
+                                     void* add_arg);
+  static void TokenBindingFreeCallback(SSL* ssl,
+                                       unsigned int extension_value,
+                                       const uint8_t* out,
+                                       void* add_arg);
+  static int TokenBindingParseCallback(SSL* ssl,
+                                       unsigned int extension_value,
+                                       const uint8_t* contents,
+                                       size_t contents_len,
+                                       int* out_alert_value,
+                                       void* parse_arg);
+
+  int TokenBindingAdd(const uint8_t** out,
+                      size_t* out_len,
+                      int* out_alert_value);
+  int TokenBindingParse(const uint8_t* contents,
+                        size_t contents_len,
+                        int* out_alert_value);
+
   bool transport_send_busy_;
   bool transport_recv_busy_;
 
@@ -281,6 +307,8 @@ class SSLClientSocketOpenSSL : public SSLClientSocket {
 
   // The service for retrieving Channel ID keys.  May be NULL.
   ChannelIDService* channel_id_service_;
+  bool tb_was_negotiated_;
+  TokenBindingParam tb_negotiated_param_;
 
   // OpenSSL stuff
   SSL* ssl_;