[webcrypto] Fix a leak in RSA private key import using JWK.

content/child/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/child/webcrypto/platform_crypto.h"
 
 #include <cryptohi.h>
 #include <pk11pub.h>
 #include <secerr.h>
 #include <sechash.h>
@@ skipping 1591 matching lines @@
 
   // The ID isn't guaranteed to be set by PKCS#11. However it is by softtoken so
   // this should work.
   SECItem object_id = {};
   if (PK11_ReadRawAttribute(
           PK11_TypeGeneric, key_object.get(), CKA_ID, &object_id) != SECSuccess)
     return Status::OperationError();
 
   crypto::ScopedSECKEYPrivateKey private_key(
       PK11_FindKeyByKeyID(slot.get(), &object_id, NULL));
+
+  SECITEM_FreeItem(&object_id, PR_FALSE);
+
   if (!private_key)
     return Status::OperationError();
 
   blink::WebCryptoKeyAlgorithm key_algorithm;
   if (!CreatePrivateKeyAlgorithm(algorithm, private_key.get(), &key_algorithm))
     return Status::ErrorUnexpected();
 
   scoped_ptr<PrivateKey> key_handle;
   Status status =
       PrivateKey::Create(private_key.Pass(), key_algorithm, &key_handle);
@@ skipping 189 matching lines @@
                                      key_algorithm,
                                      usage_mask);
   return Status::Success();
 }
 
 }  // namespace platform
 
 }  // namespace webcrypto
 
 }  // namespace content