Remove dependency of SSLPlatformKeyTaskRunner on single-threaded SequencedWorkerPool.

net/ssl/ssl_platform_key_mac.cc

 // 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 "net/ssl/ssl_platform_key.h"
 
 #include <Security/SecBase.h>
 #include <Security/SecCertificate.h>
 #include <Security/SecIdentity.h>
 #include <Security/SecKey.h>
@@ skipping 226 matching lines @@
   if (status != noErr)
     return nullptr;
 
   if (cssm_key->KeyHeader.AlgorithmId != CSSM_ALGID_RSA &&
       cssm_key->KeyHeader.AlgorithmId != CSSM_ALGID_ECDSA) {
     LOG(ERROR) << "Unknown key type: " << cssm_key->KeyHeader.AlgorithmId;
     return nullptr;
   }
   return make_scoped_refptr(new ThreadedSSLPrivateKey(
       base::WrapUnique(new SSLPlatformKeyMac(private_key.get(), cssm_key)),
-      GetSSLPlatformKeyTaskRunner()));
+      SSLPlatformKeyTaskRunner::Get()));
 }
 
 #pragma clang diagnostic pop  // "-Wdeprecated-declarations"
 
 }  // namespace net