Refactor client cert private key handling.

net/ssl/ssl_platform_key_mac.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_SSL_PLATFORM_KEY_MAC_H_
 #define NET_SSL_SSL_PLATFORM_KEY_MAC_H_
 
 #include <Security/SecBase.h>
 
 #include "base/memory/ref_counted.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 class SSLPrivateKey;
 class X509Certificate;
 
-// Returns an SSLPrivateKey backed by the platform private key in |keychain|
-// that corresponds to |certificate|'s public key. If |keychain| is nullptr, the
-// user's default search list is used instead.
-NET_EXPORT_PRIVATE scoped_refptr<SSLPrivateKey>
-FetchClientCertPrivateKeyFromKeychain(const X509Certificate* certificate,
-                                      SecKeychainRef keychain);
+// Returns an SSLPrivateKey backed by the platform private key in |identity|
+// which must correspond to |certificate|'s public key.
+NET_EXPORT scoped_refptr<SSLPrivateKey> CreateSSLPrivateKeyForSecIdentity(
+    const X509Certificate* certificate,
+    SecIdentityRef identity);
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_PLATFORM_KEY_MAC_H_