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

content/child/webcrypto/nss/sym_key_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/nss/sym_key_nss.h"
 
 #include "base/logging.h"
 #include "content/child/webcrypto/crypto_data.h"
 #include "content/child/webcrypto/generate_key_result.h"
 #include "content/child/webcrypto/nss/key_nss.h"
 #include "content/child/webcrypto/nss/util_nss.h"
 #include "content/child/webcrypto/status.h"
 #include "content/child/webcrypto/webcrypto_util.h"
 #include "crypto/scoped_nss_types.h"
 #include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
 
 namespace content {
 
 namespace webcrypto {
 
 Status GenerateSecretKeyNss(const blink::WebCryptoKeyAlgorithm& algorithm,
                             bool extractable,
                             blink::WebCryptoKeyUsageMask usages,
                             unsigned keylen_bytes,
                             CK_MECHANISM_TYPE mechanism,
                             GenerateKeyResult* result) {
   DCHECK_NE(CKM_INVALID_MECHANISM, mechanism);
 
-  if (usages == 0)
-    return Status::ErrorCreateKeyEmptyUsages();
-
   crypto::ScopedPK11Slot slot(PK11_GetInternalKeySlot());
   if (!slot)
     return Status::OperationError();
 
   crypto::ScopedPK11SymKey pk11_key(
       PK11_KeyGen(slot.get(), mechanism, NULL, keylen_bytes, NULL));
 
   if (!pk11_key)
     return Status::OperationError();
 
@@ skipping 46 matching lines @@
                                      blink::WebCryptoKeyTypeSecret,
                                      extractable,
                                      algorithm,
                                      usages);
   return Status::Success();
 }
 
 }  // namespace webcrypto
 
 }  // namespace content