[webcrypto] Add length parameter to HmacKeyAlgorithm. (blink)

Source/modules/crypto/HmacKeyAlgorithm.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 22 matching lines @@
 
 #include "modules/crypto/KeyAlgorithm.h"
 
 namespace WebCore {
 
 class HmacKeyAlgorithm : public KeyAlgorithm {
 public:
     static PassRefPtrWillBeRawPtr<HmacKeyAlgorithm> create(const blink::WebCryptoKeyAlgorithm&);
 
     KeyAlgorithm* hash();
+    unsigned length();
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     explicit HmacKeyAlgorithm(const blink::WebCryptoKeyAlgorithm&);
 
     RefPtrWillBeMember<KeyAlgorithm> m_hash;
 };
 
 DEFINE_KEY_ALGORITHM_TYPE_CASTS(HmacKeyAlgorithm);
 
 } // namespace WebCore
 
 #endif