Sign CertificateVerify messages on a background thread.

net/ssl/openssl_platform_key_nss.cc

Index: net/ssl/openssl_platform_key_nss.cc
diff --git a/net/ssl/openssl_platform_key_nss.cc b/net/ssl/openssl_platform_key_nss.cc
deleted file mode 100644
index a9471e4452301d3e8d3b5eb86bd1b569d2476759..0000000000000000000000000000000000000000
--- a/net/ssl/openssl_platform_key_nss.cc
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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.
-
-#include "base/logging.h"
-#include "net/ssl/openssl_platform_key.h"
-
-namespace net {
-
-crypto::ScopedEVP_PKEY FetchClientCertPrivateKey(
-    const X509Certificate* certificate) {
-  // TODO(davidben): Implement client auth for NSS. https://crbug.com/479036
-  NOTIMPLEMENTED();
-  return nullptr;
-}
-
-}  // namespace net