external/boringssl: Sync to 27bc0f26c8d132df04f5b0b173aefeb8aaa13c33.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/ba8f1864c15ec938ce0851f416663511c89f454a..27bc0f26c8d132df04f5b0b173aefeb8aaa13c33

Test: BoringSSL CTS Presubmits
Change-Id: Id63dac9fa22a3b41609f55bfe48d2cfaa53b25c6
diff --git a/src/include/openssl/dsa.h b/src/include/openssl/dsa.h
index 315e7ca..2966f9d 100644
--- a/src/include/openssl/dsa.h
+++ b/src/include/openssl/dsa.h
@@ -172,7 +172,7 @@
 // DSA_do_sign returns a signature of the hash in |digest| by the key in |dsa|
 // and returns an allocated, DSA_SIG structure, or NULL on error.
 OPENSSL_EXPORT DSA_SIG *DSA_do_sign(const uint8_t *digest, size_t digest_len,
-                                    DSA *dsa);
+                                    const DSA *dsa);
 
 // DSA_do_verify verifies that |sig| is a valid signature, by the public key in
 // |dsa|, of the hash in |digest|. It returns one if so, zero if invalid and -1
@@ -212,7 +212,7 @@
 // (The |type| argument is ignored.)
 OPENSSL_EXPORT int DSA_sign(int type, const uint8_t *digest, size_t digest_len,
                             uint8_t *out_sig, unsigned int *out_siglen,
-                            DSA *dsa);
+                            const DSA *dsa);
 
 // DSA_verify verifies that |sig| is a valid, ASN.1 signature, by the public
 // key in |dsa|, of the hash in |digest|. It returns one if so, zero if invalid
@@ -284,19 +284,6 @@
 OPENSSL_EXPORT int DSA_marshal_parameters(CBB *cbb, const DSA *dsa);
 
 
-// Precomputation.
-
-// DSA_sign_setup precomputes the message independent part of the DSA signature
-// and writes them to |*out_kinv| and |*out_r|. Returns one on success, zero on
-// error.
-//
-// TODO(fork): decide what to do with this. Since making DSA* opaque there's no
-// way for the user to install them. Also, it forces the DSA* not to be const
-// when passing to the signing function.
-OPENSSL_EXPORT int DSA_sign_setup(const DSA *dsa, BN_CTX *ctx,
-                                  BIGNUM **out_kinv, BIGNUM **out_r);
-
-
 // Conversion.
 
 // DSA_dup_DH returns a |DH| constructed from the parameters of |dsa|. This is
@@ -411,9 +398,6 @@
   BIGNUM *pub_key;   // y public key
   BIGNUM *priv_key;  // x private key
 
-  BIGNUM *kinv;  // Signing pre-calc
-  BIGNUM *r;     // Signing pre-calc
-
   int flags;
   // Normally used to cache montgomery values
   CRYPTO_MUTEX method_mont_lock;