Refactor client cert private key handling.

net/ssl/ssl_platform_key_win.h

 // Copyright 2017 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_WIN_H_
 #define NET_SSL_SSL_PLATFORM_KEY_WIN_H_
 
 #include <windows.h>
 
 // Must be after windows.h.
 #include <NCrypt.h>
 
 #include "base/memory/ref_counted.h"
 #include "crypto/wincrypt_shim.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 class SSLPrivateKey;
 class X509Certificate;
 
+// Returns an SSLPrivateKey backed by the platform private key for
+// |cert_context| which must correspond to |certificate|.
+scoped_refptr<SSLPrivateKey> FetchClientCertPrivateKey(
+    const X509Certificate* certificate,
+    PCCERT_CONTEXT cert_context);
+
 // Returns an SSLPrivateKey backed by |prov| and |key_spec|, which must
 // correspond to |certificate|'s public key. Takes ownership of |prov|.
 NET_EXPORT_PRIVATE scoped_refptr<SSLPrivateKey> WrapCAPIPrivateKey(
     const X509Certificate* certificate,
     HCRYPTPROV prov,
     DWORD key_spec);
 
 // Returns an SSLPrivateKey backed by |key|, which must correspond to
 // |certificate|'s public key, or nullptr on error. Takes ownership of |key| in
 // both cases.
 NET_EXPORT_PRIVATE scoped_refptr<SSLPrivateKey> WrapCNGPrivateKey(
     const X509Certificate* certificate,
     NCRYPT_KEY_HANDLE key);
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_PLATFORM_KEY_WIN_H_