Sign CertificateVerify messages on a background thread.

net/ssl/ssl_platform_key.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_H_
+#define NET_SSL_SSL_PLATFORM_KEY_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace net {
+
+class SSLPrivateKey;
+class X509Certificate;
+
+// Looks up the private key from the platform key store corresponding to
+// |certificate|'s public key and returns an SSLPrivateKey which offloads
+// signing operations to |task_runner|. |task_runner| is a SequencedTaskRunner
+// to allow for buggy third-party smartcard drivers.
+scoped_ptr<SSLPrivateKey> FetchClientCertPrivateKey(
+    X509Certificate* certificate,
+    scoped_refptr<base::SequencedTaskRunner> task_runner);
+
+}  // namespace net
+
+#endif  // NET_SSL_SSL_PLATFORM_KEY_H_