Pass explicit hs parameters to kExtensions callbacks.

This takes care of many of the explicit ssl->s3->hs accesses.

Change-Id: I380fae959f3a7021d6de9d19a4ca451b9a0aefe5
Reviewed-on: https://boringssl-review.googlesource.com/12317
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/tls13_client.c b/ssl/tls13_client.c
index 9e71f31..7a93103 100644
--- a/ssl/tls13_client.c
+++ b/ssl/tls13_client.c
@@ -143,7 +143,7 @@
 }
 
 static enum ssl_hs_wait_t do_send_second_client_hello(SSL_HANDSHAKE *hs) {
-  if (!ssl_write_client_hello(hs->ssl)) {
+  if (!ssl_write_client_hello(hs)) {
     return ssl_hs_error;
   }
 
@@ -328,7 +328,7 @@
 
   CBS cbs;
   CBS_init(&cbs, ssl->init_msg, ssl->init_num);
-  if (!ssl_parse_serverhello_tlsext(ssl, &cbs)) {
+  if (!ssl_parse_serverhello_tlsext(hs, &cbs)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
     return ssl_hs_error;
   }