[webcrypto] Add the KeyAlgorithm interface.

Source/modules/crypto/HmacKeyAlgorithm.cpp

Index: Source/modules/crypto/HmacKeyAlgorithm.cpp
diff --git a/Source/modules/crypto/Algorithm.cpp b/Source/modules/crypto/HmacKeyAlgorithm.cpp
similarity index 72%
copy from Source/modules/crypto/Algorithm.cpp
copy to Source/modules/crypto/HmacKeyAlgorithm.cpp
index 35568ff46e53cd840dc945fad6df50f12beff7be..5d42b817f645488637f81a2878ea7372e33f32c8 100644
--- a/Source/modules/crypto/Algorithm.cpp
+++ b/Source/modules/crypto/HmacKeyAlgorithm.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Google Inc. All rights reserved.
+ * 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
@@ -29,27 +29,35 @@
  */
 
 #include "config.h"
-#include "modules/crypto/Algorithm.h"
+#include "modules/crypto/HmacKeyAlgorithm.h"
 
 #include "modules/crypto/NormalizeAlgorithm.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
-PassRefPtrWillBeRawPtr<Algorithm> Algorithm::create(const blink::WebCryptoAlgorithm& algorithm)
+PassRefPtrWillBeRawPtr<HmacKeyAlgorithm> HmacKeyAlgorithm::create(const blink::WebCryptoKeyAlgorithm& algorithm)
 {
-    return adoptRefWillBeNoop(new Algorithm(algorithm));
+    return adoptRefWillBeNoop(new HmacKeyAlgorithm(algorithm));
 }
 
-Algorithm::Algorithm(const blink::WebCryptoAlgorithm& algorithm)
-    : m_algorithm(algorithm)
+KeyAlgorithm* HmacKeyAlgorithm::hash()
 {
-    ScriptWrappable::init(this);
+    if (!m_hash)
+        m_hash = KeyAlgorithm::createHash(m_algorithm.hmacParams()->hash());
+    return m_hash.get();
 }
 
-String Algorithm::name()
+void HmacKeyAlgorithm::trace(Visitor* visitor)
 {
-    return algorithmIdToName(m_algorithm.id());
+    KeyAlgorithm::trace(visitor);
+    visitor->trace(m_hash);
+}
+
+HmacKeyAlgorithm::HmacKeyAlgorithm(const blink::WebCryptoKeyAlgorithm& algorithm)
+    : KeyAlgorithm(algorithm)
+{
+    ScriptWrappable::init(this);
 }
 
 } // namespace WebCore