Lift BIO above SSL_PROTOCOL_METHOD.

This gets us closer to exposing BIO-free APIs. The next step is probably
to make the experimental bssl::OpenRecord function call a split out core
of ssl_read_impl.

Change-Id: I4acebb43f708df8c52eb4e328da8ae3551362fb9
Reviewed-on: https://boringssl-review.googlesource.com/21865
Commit-Queue: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Steven Valdez <svaldez@google.com>
diff --git a/ssl/dtls_method.cc b/ssl/dtls_method.cc
index a6156a1..ac06842 100644
--- a/ssl/dtls_method.cc
+++ b/ssl/dtls_method.cc
@@ -117,11 +117,11 @@
     dtls1_new,
     dtls1_free,
     dtls1_get_message,
-    dtls1_read_message,
     dtls1_next_message,
-    dtls1_read_app_data,
-    dtls1_read_change_cipher_spec,
-    dtls1_read_close_notify,
+    dtls1_open_handshake,
+    dtls1_open_change_cipher_spec,
+    dtls1_open_app_data,
+    dtls1_open_close_notify,
     dtls1_write_app_data,
     dtls1_dispatch_alert,
     dtls1_supports_cipher,