[webcrypto] Wire up {spki, pkcs8} import/export for OpenSSL.

content/child/webcrypto/openssl/util_openssl.cc

 // Copyright 2014 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 "content/child/webcrypto/openssl/util_openssl.h"
 
 #include <openssl/evp.h>
 
 #include "content/child/webcrypto/crypto_data.h"
 #include "content/child/webcrypto/platform_crypto.h"
@@ skipping 20 matching lines @@
     default:
       return NULL;
   }
 }
 
 AlgorithmImplementation* CreatePlatformRsaOaepImplementation() {
   // TODO(eroman):
   return NULL;
 }
 
-AlgorithmImplementation* CreatePlatformRsaSsaImplementation() {
-  // TODO(eroman):
-  return NULL;
-}
-
 }  // namespace webcrypto
 
 }  // namespace content