WebCrypto: Add parsing for the algorithm parameter AesDerivedKey.

public/platform/WebCryptoAlgorithmParams.h

Index: public/platform/WebCryptoAlgorithmParams.h
diff --git a/public/platform/WebCryptoAlgorithmParams.h b/public/platform/WebCryptoAlgorithmParams.h
index e617f086c082441c5b368fd02d329c5bf933b6ca..3f1c8078098b2403c79280ce6734057a5af865de 100644
--- a/public/platform/WebCryptoAlgorithmParams.h
+++ b/public/platform/WebCryptoAlgorithmParams.h
@@ -322,6 +322,21 @@ private:
     const WebCryptoKey m_publicKey;
 };
 
+class WebCryptoAesDerivedKeyParams : public WebCryptoAlgorithmParams {
+public:
+    explicit WebCryptoAesDerivedKeyParams(unsigned short lengthBits)
+        : m_lengthBits(lengthBits)
+    {
+    }
+
+    virtual WebCryptoAlgorithmParamsType type() const override { return WebCryptoAlgorithmParamsTypeAesDerivedKeyParams; }
+
+    unsigned short lengthBits() const { return m_lengthBits; }
+
+private:
+    const unsigned short m_lengthBits;
+};
+
 } // namespace blink
 
 #endif