Implement HKDF for WebCrypto (blink-side)

Source/platform/exported/WebCryptoKeyAlgorithm.cpp

 /*
  * 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 75 matching lines @@
     if (!WebCryptoAlgorithm::isHash(hash))
         return WebCryptoKeyAlgorithm();
     return WebCryptoKeyAlgorithm(id, adoptPtr(new WebCryptoRsaHashedKeyAlgorithmParams(modulusLengthBits, publicExponent, publicExponentSize, createHash(hash))));
 }
 
 WebCryptoKeyAlgorithm WebCryptoKeyAlgorithm::createEc(WebCryptoAlgorithmId id, WebCryptoNamedCurve namedCurve)
 {
     return WebCryptoKeyAlgorithm(id, adoptPtr(new WebCryptoEcKeyAlgorithmParams(namedCurve)));
 }
 
+WebCryptoKeyAlgorithm WebCryptoKeyAlgorithm::createWithoutParams(WebCryptoAlgorithmId id)
+{
+    if (!WebCryptoAlgorithm::isKdf(id))
+        return WebCryptoKeyAlgorithm();
+    return WebCryptoKeyAlgorithm(id, nullptr);
+}
+
 bool WebCryptoKeyAlgorithm::isNull() const
 {
     return m_private.isNull();
 }
 
 WebCryptoAlgorithmId WebCryptoKeyAlgorithm::id() const
 {
     ASSERT(!isNull());
     return m_private->id;
 }
@@ skipping 35 matching lines @@
     ASSERT(!isNull());
     if (paramsType() == WebCryptoKeyAlgorithmParamsTypeEc)
         return static_cast<WebCryptoEcKeyAlgorithmParams*>(m_private->params.get());
     return 0;
 }
 
 void WebCryptoKeyAlgorithm::writeToDictionary(WebCryptoKeyAlgorithmDictionary* dict) const
 {
     ASSERT(!isNull());
     dict->setString("name", WebCryptoAlgorithm::lookupAlgorithmInfo(id())->name);
-    m_private->params.get()->writeToDictionary(dict);
+    if (m_private->params.get())
+        m_private->params.get()->writeToDictionary(dict);
 }
 
 void WebCryptoKeyAlgorithm::assign(const WebCryptoKeyAlgorithm& other)
 {
     m_private = other.m_private;
 }
 
 void WebCryptoKeyAlgorithm::reset()
 {
     m_private.reset();
 }
 
 } // namespace blink