Go through SSL_PROTOCOL_METHOD in the handshake.

The handshake should be generic between TLS and DTLS.

Change-Id: I6feb2f013dd5d771f206750653ab9d117d7ea716
Reviewed-on: https://boringssl-review.googlesource.com/21348
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>

ssl/tls13_client.cc

diff --git a/ssl/tls13_client.cc b/ssl/tls13_client.cc
index 7ed9fad..b02ee14 100644
--- a/ssl/tls13_client.cc
+++ b/ssl/tls13_client.cc
@@ -357,7 +357,7 @@
     // If not sending early data, set client traffic keys now so that alerts are
     // encrypted.
     if ((ssl_is_resumption_client_ccs_experiment(ssl->version) &&
-         !ssl3_add_change_cipher_spec(ssl)) ||
+         !ssl->method->add_change_cipher_spec(ssl)) ||
         !tls13_set_traffic_key(ssl, evp_aead_seal, hs->client_handshake_secret,
                                hs->hash_len)) {
       return ssl_hs_error;
@@ -565,7 +565,7 @@
 
   if (hs->early_data_offered) {
     if ((ssl_is_resumption_client_ccs_experiment(ssl->version) &&
-         !ssl3_add_change_cipher_spec(ssl)) ||
+         !ssl->method->add_change_cipher_spec(ssl)) ||
         !tls13_set_traffic_key(ssl, evp_aead_seal, hs->client_handshake_secret,
                                hs->hash_len)) {
       return ssl_hs_error;

ssl/tls13_server.cc

diff --git a/ssl/tls13_server.cc b/ssl/tls13_server.cc
index e372a0d..f89e766 100644
--- a/ssl/tls13_server.cc
+++ b/ssl/tls13_server.cc
@@ -552,7 +552,7 @@
   }
 
   if (ssl_is_resumption_experiment(ssl->version) &&
-      !ssl3_add_change_cipher_spec(ssl)) {
+      !ssl->method->add_change_cipher_spec(ssl)) {
     return ssl_hs_error;
   }