Fix memory leak from use of SECKEY_ConvertToPublicKey().

content/renderer/webcrypto/platform_crypto_nss.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/renderer/webcrypto/platform_crypto.h"
 
 #include <cryptohi.h>
 #include <pk11pub.h>
 #include <sechash.h>
 
@@ skipping 423 matching lines @@
               public_exponent.byte_length()));
       return true;
     default:
       return false;
   }
 }
 
 bool CreatePrivateKeyAlgorithm(const blink::WebCryptoAlgorithm& algorithm,
                                SECKEYPrivateKey* key,
                                blink::WebCryptoKeyAlgorithm* key_algorithm) {
-  return CreatePublicKeyAlgorithm(
-      algorithm, SECKEY_ConvertToPublicKey(key), key_algorithm);
+  crypto::ScopedSECKEYPublicKey public_key(SECKEY_ConvertToPublicKey(key));
+  return CreatePublicKeyAlgorithm(algorithm, public_key.get(), key_algorithm);
 }
 
 }  // namespace
 
 Status ImportKeyRaw(const blink::WebCryptoAlgorithm& algorithm,
                     const CryptoData& key_data,
                     bool extractable,
                     blink::WebCryptoKeyUsageMask usage_mask,
                     blink::WebCryptoKey* key) {
 
@@ skipping 642 matching lines @@
                                      key_algorithm,
                                      usage_mask);
   return Status::Success();
 }
 
 }  // namespace platform
 
 }  // namespace webcrypto
 
 }  // namespace content