[webcrypto] Add the KeyAlgorithm interface.

Source/modules/crypto/RsaKeyAlgorithm.h

Index: Source/modules/crypto/RsaKeyAlgorithm.h
diff --git a/Source/platform/fonts/FontCacheClient.h b/Source/modules/crypto/RsaKeyAlgorithm.h
similarity index 77%
copy from Source/platform/fonts/FontCacheClient.h
copy to Source/modules/crypto/RsaKeyAlgorithm.h
index 4e43b8c72cf93e9d6f51f68098d434a9d97444ce..13be268506b1a1042fcf6582974c45fbee232e1f 100644
--- a/Source/platform/fonts/FontCacheClient.h
+++ b/Source/modules/crypto/RsaKeyAlgorithm.h
@@ -28,21 +28,29 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef FontCacheClient_h
-#define FontCacheClient_h
+#ifndef RsaKeyAlgorithm_h
+#define RsaKeyAlgorithm_h
 
-#include "platform/PlatformExport.h"
-#include "wtf/RefCounted.h"
+#include "modules/crypto/KeyAlgorithm.h"
 
 namespace WebCore {
 
-class PLATFORM_EXPORT FontCacheClient : public RefCounted<FontCacheClient> {
+class RsaKeyAlgorithm : public KeyAlgorithm {
 public:
-    virtual ~FontCacheClient() { }
+    ~RsaKeyAlgorithm();
 
-    virtual void fontCacheInvalidated() = 0;
+    static PassRefPtrWillBeRawPtr<RsaKeyAlgorithm> create(const blink::WebCryptoKeyAlgorithm&);
+
+    unsigned modulusLength();
+    Uint8Array* publicExponent();
+
+    void trace(Visitor*);
+
+protected:
+    explicit RsaKeyAlgorithm(const blink::WebCryptoKeyAlgorithm&);
+    RefPtr<Uint8Array> m_publicExponent;
 };
 
 } // namespace WebCore
 
-#endif // FontCacheClient_h
+#endif