Check that usage isn't empty when generateKey() is called

content/child/webcrypto/openssl/ec_key_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/ec_key_openssl.h"
 
 #include <openssl/ec.h>
 #include <openssl/ec_key.h>
 #include <openssl/evp.h>
 #include <openssl/pkcs12.h>
@@ skipping 200 matching lines @@
   Status status = CheckKeyCreationUsages(
       all_public_key_usages_ | all_private_key_usages_, combined_usages);
   if (status.IsError())
     return status;
 
   const blink::WebCryptoKeyUsageMask public_usages =
       combined_usages & all_public_key_usages_;
   const blink::WebCryptoKeyUsageMask private_usages =
       combined_usages & all_private_key_usages_;
 
+  if (private_usages == 0)
+    return Status::ErrorCreateKeyEmptyUsages();
+
   const blink::WebCryptoEcKeyGenParams* params = algorithm.ecKeyGenParams();
 
   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 
   // Generate an EC key pair.
   crypto::ScopedEC_KEY ec_private_key;
   status = CreateEC_KEY(params->namedCurve(), &ec_private_key);
   if (status.IsError())
     return status;
 
@@ skipping 337 matching lines @@
       key->algorithm().ecParams()->namedCurve()) {
     return Status::ErrorUnexpected();
   }
 
   return Status::Success();
 }
 
 }  // namespace webcrypto
 
 }  // namespace content