Remove legacy SSL_CTX_sess_set_get_cb overload.

Update-Note: I believe everything relying on this overload has since
    been updated.

Change-Id: I7facf59cde56098e5e3c79470293b67abb715f4c
Reviewed-on: https://boringssl-review.googlesource.com/27485
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

include/openssl/ssl.h

@@ -4116,16 +4116,6 @@ OPENSSL_EXPORT SSL_SESSION *SSL_get1_session(SSL *ssl);
 OPENSSL_EXPORT int OPENSSL_init_ssl(uint64_t opts,
                                     const OPENSSL_INIT_SETTINGS *settings);
 
-#if !defined(BORINGSSL_NO_CXX)
-// SSL_CTX_sess_set_get_cb is a legacy C++ overload of |SSL_CTX_sess_set_get_cb|
-// which supports the old callback signature.
-//
-// TODO(davidben): Remove this once Node is compatible with OpenSSL 1.1.0.
-extern "C++" OPENSSL_EXPORT void SSL_CTX_sess_set_get_cb(
-    SSL_CTX *ctx, SSL_SESSION *(*get_session_cb)(SSL *ssl, uint8_t *id,
-                                                 int id_len, int *out_copy));
-#endif
-
 
 // Private structures.
 //

ssl/internal.h

@@ -2027,8 +2027,6 @@ struct SSLContext {
   void (*remove_session_cb)(SSL_CTX *ctx, SSL_SESSION *sess);
   SSL_SESSION *(*get_session_cb)(SSL *ssl, const uint8_t *data, int len,
                                  int *copy);
-  SSL_SESSION *(*get_session_cb_legacy)(SSL *ssl, uint8_t *data, int len,
-                                        int *copy);
 
   CRYPTO_refcount_t references;
 

ssl/ssl_session.cc

@@ -682,17 +682,10 @@ static enum ssl_hs_wait_t ssl_lookup_session(
   }
 
   // Fall back to the external cache, if it exists.
-  if (!session && (ssl->session_ctx->get_session_cb != nullptr ||
-                   ssl->session_ctx->get_session_cb_legacy != nullptr)) {
+  if (!session && ssl->session_ctx->get_session_cb != nullptr) {
     int copy = 1;
-    if (ssl->session_ctx->get_session_cb != nullptr) {
-      session.reset(ssl->session_ctx->get_session_cb(ssl, session_id,
-                                                     session_id_len, &copy));
-    } else {
-      session.reset(ssl->session_ctx->get_session_cb_legacy(
-          ssl, const_cast<uint8_t *>(session_id), session_id_len, &copy));
-    }
-
+    session.reset(ssl->session_ctx->get_session_cb(ssl, session_id,
+                                                   session_id_len, &copy));
     if (!session) {
       return ssl_hs_ok;
     }
@@ -1192,12 +1185,6 @@ void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
   ctx->get_session_cb = cb;
 }
 
-void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
-                             SSL_SESSION *(*cb)(SSL *ssl, uint8_t *id,
-                                                int id_len, int *out_copy)) {
-  ctx->get_session_cb_legacy = cb;
-}
-
 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(SSL *ssl,
                                                       const uint8_t *id,
                                                       int id_len,