Adding Post-Handshake message handling.

Change-Id: I5cc194fc0a3ba8283049078e5671c924ee23036c
Reviewed-on: https://boringssl-review.googlesource.com/8980
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/internal.h b/ssl/internal.h
index e3d0463..14265f9 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -905,6 +905,10 @@
 enum ssl_hs_wait_t tls13_client_handshake(SSL *ssl);
 enum ssl_hs_wait_t tls13_server_handshake(SSL *ssl);
 
+/* tls13_post_handshake processes a post-handshake message. It returns one on
+ * success and zero on failure. */
+int tls13_post_handshake(SSL *ssl);
+
 /* tls13_check_message_type checks if the current message has type |type|. If so
  * it returns one. Otherwise, it sends an alert and returns zero. */
 int tls13_check_message_type(SSL *ssl, int type);