Convert SSL_TRANSCRIPT to C++.

Bug: 132
Change-Id: I2d7cb45d56e8dcb223fbc5838922fdbe6f28ded7
Reviewed-on: https://boringssl-review.googlesource.com/18264
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/tls13_both.cc b/ssl/tls13_both.cc
index 90fbf1c..338975b 100644
--- a/ssl/tls13_both.cc
+++ b/ssl/tls13_both.cc
@@ -181,8 +181,7 @@
 
   uint8_t context_hash[EVP_MAX_MD_SIZE];
   size_t context_hash_len;
-  if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, context_hash,
-                               &context_hash_len) ||
+  if (!hs->transcript.GetHash(context_hash, &context_hash_len) ||
       !CBB_add_bytes(cbb.get(), context_hash, context_hash_len) ||
       !CBB_finish(cbb.get(), out, out_len)) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);