Add SSL_CIPHER_has_SHA256_HMAC.

Change-Id: I05a8f5d1778aba1813fe4d34b4baa21849158218
Reviewed-on: https://boringssl-review.googlesource.com/7215
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/ssl_cipher.c b/ssl/ssl_cipher.c
index 4ff9f5c..7aa4a6f 100644
--- a/ssl/ssl_cipher.c
+++ b/ssl/ssl_cipher.c
@@ -1577,6 +1577,10 @@
   return (cipher->algorithm_mac & SSL_SHA1) != 0;
 }
 
+int SSL_CIPHER_has_SHA256_HMAC(const SSL_CIPHER *cipher) {
+  return (cipher->algorithm_mac & SSL_SHA256) != 0;
+}
+
 int SSL_CIPHER_is_AESGCM(const SSL_CIPHER *cipher) {
   return (cipher->algorithm_enc & (SSL_AES128GCM | SSL_AES256GCM)) != 0;
 }