Refactor client cert private key handling.

net/ssl/test_ssl_private_key.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SSL_TEST_SSL_PRIVATE_KEY_H_
 #define NET_SSL_TEST_SSL_PRIVATE_KEY_H_
 
 #include "base/memory/ref_counted.h"
 #include "net/base/net_export.h"
 #include "third_party/boringssl/src/include/openssl/base.h"
 
+namespace crypto {
+class RSAPrivateKey;
+}
+
 namespace net {
 
 class SSLPrivateKey;
 
 // Returns a new SSLPrivateKey which uses |key| for signing operations or
 // nullptr on error.
 NET_EXPORT scoped_refptr<SSLPrivateKey> WrapOpenSSLPrivateKey(
     bssl::UniquePtr<EVP_PKEY> key);
+NET_EXPORT scoped_refptr<SSLPrivateKey> WrapRSAPrivateKey(
+    crypto::RSAPrivateKey* rsa_private_key);
 
 }  // namespace net
 
 #endif  // NET_SSL_TEST_SSL_PRIVATE_KEY_H_