Refactor client cert private key handling.

net/ssl/ssl_platform_key_nss.h

+// Copyright 2015 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_SSL_PLATFORM_KEY_NSS_H_
+#define NET_SSL_SSL_PLATFORM_KEY_NSS_H_
+
+#include <memory>
+
+#include "base/memory/ref_counted.h"
+#include "net/base/net_export.h"
+
+namespace crypto {
+class CryptoModuleBlockingPasswordDelegate;
+}
+
+namespace net {
+
+class SSLPrivateKey;
+class X509Certificate;
+
+// Returns an SSLPrivateKey backed by the NSS private key that corresponds to
+// |certificate|'s public key. If |password_delegate| is non-null, it will be
+// used to prompt for a password if necessary to unlock a slot.
+NET_EXPORT scoped_refptr<SSLPrivateKey> FetchClientCertPrivateKey(
+    const X509Certificate* certificate,
+    crypto::CryptoModuleBlockingPasswordDelegate* password_delegate);
+
+}  // namespace net
+
+#endif  // NET_SSL_SSL_PLATFORM_KEY_NSS_H_