Add a Wycheproof driver for AES-CBC.

Change-Id: I782ea51e1db8d05f552832a7c6910954fa2dda5f
Reviewed-on: https://boringssl-review.googlesource.com/27924
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/cipher.h b/include/openssl/cipher.h
index 643bf04..1db81ae 100644
--- a/include/openssl/cipher.h
+++ b/include/openssl/cipher.h
@@ -243,6 +243,10 @@
 // configured.
 OPENSSL_EXPORT int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx);
 
+// EVP_CIPHER_CTX_encrypting returns one if |ctx| is configured for encryption
+// and zero otherwise.
+OPENSSL_EXPORT int EVP_CIPHER_CTX_encrypting(const EVP_CIPHER_CTX *ctx);
+
 // EVP_CIPHER_CTX_block_size returns the block size, in bytes, of the cipher
 // underlying |ctx|, or one if the cipher is a stream cipher. It will crash if
 // no cipher has been configured.