Implement HKDF for WebCrypto (blink-side)

public/platform/WebCryptoKeyAlgorithm.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 45 matching lines @@
     BLINK_PLATFORM_EXPORT WebCryptoKeyAlgorithm(WebCryptoAlgorithmId, PassOwnPtr<WebCryptoKeyAlgorithmParams>);
 #endif
 
     // FIXME: Delete this in favor of the create*() functions.
     BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm adoptParamsAndCreate(WebCryptoAlgorithmId, WebCryptoKeyAlgorithmParams*);
 
     BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm createAes(WebCryptoAlgorithmId, unsigned short keyLengthBits);
     BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm createHmac(WebCryptoAlgorithmId hash, unsigned keyLengthBits);
     BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm createRsaHashed(WebCryptoAlgorithmId, unsigned modulusLengthBits, const unsigned char* publicExponent, unsigned publicExponentSize, WebCryptoAlgorithmId hash);
     BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm createEc(WebCryptoAlgorithmId, WebCryptoNamedCurve);
+    BLINK_PLATFORM_EXPORT static WebCryptoKeyAlgorithm createKdf(WebCryptoAlgorithmId);
 
     ~WebCryptoKeyAlgorithm() { reset(); }
 
     WebCryptoKeyAlgorithm(const WebCryptoKeyAlgorithm& other) { assign(other); }
     WebCryptoKeyAlgorithm& operator=(const WebCryptoKeyAlgorithm& other)
     {
         assign(other);
         return *this;
     }
 
@@ skipping 17 matching lines @@
 private:
     BLINK_PLATFORM_EXPORT void assign(const WebCryptoKeyAlgorithm& other);
     BLINK_PLATFORM_EXPORT void reset();
 
     WebPrivatePtr<WebCryptoKeyAlgorithmPrivate> m_private;
 };
 
 } // namespace blink
 
 #endif