[webcrypto] Add the KeyAlgorithm interface.

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 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef FontCacheClient_h
-#define FontCacheClient_h
+#ifndef HmacKeyAlgorithm_h
+#define HmacKeyAlgorithm_h
 
-#include "platform/PlatformExport.h"
-#include "wtf/RefCounted.h"
+#include "modules/crypto/KeyAlgorithm.h"
 
 namespace WebCore {
 
-class PLATFORM_EXPORT FontCacheClient : public RefCounted<FontCacheClient> {
+class HmacKeyAlgorithm : public KeyAlgorithm {
 public:
-    virtual ~FontCacheClient() { }
+    static PassRefPtrWillBeRawPtr<HmacKeyAlgorithm> create(const blink::WebCryptoKeyAlgorithm&);
 
-    virtual void fontCacheInvalidated() = 0;
+    KeyAlgorithm* hash();
+
+    virtual void trace(Visitor*) OVERRIDE;
+
+private:
+    explicit HmacKeyAlgorithm(const blink::WebCryptoKeyAlgorithm&);
+
+    RefPtrWillBeMember<KeyAlgorithm> m_hash;
 };
 
+DEFINE_KEY_ALGORITHM_TYPE_CASTS(HmacKeyAlgorithm);
+
 } // namespace WebCore
 
-#endif // FontCacheClient_h
+#endif