[webcrypto] Add parameter parsing for RSA-PSS.

public/platform/WebCryptoAlgorithmParams.h

Index: public/platform/WebCryptoAlgorithmParams.h
diff --git a/public/platform/WebCryptoAlgorithmParams.h b/public/platform/WebCryptoAlgorithmParams.h
index 1038c538f1382dd51092e96133cccea24bef1437..8d8cc8705c3b7a9901b19886042b7b8afedaff4f 100644
--- a/public/platform/WebCryptoAlgorithmParams.h
+++ b/public/platform/WebCryptoAlgorithmParams.h
@@ -232,6 +232,21 @@ private:
     const WebVector<unsigned char> m_optionalLabel;
 };
 
+class WebCryptoRsaPssParams : public WebCryptoAlgorithmParams {
+public:
+    explicit WebCryptoRsaPssParams(unsigned saltLengthBytes)
+        : m_saltLengthBytes(saltLengthBytes)
+    {
+    }
+
+    virtual WebCryptoAlgorithmParamsType type() const { return WebCryptoAlgorithmParamsTypeRsaPssParams; }
+
+    unsigned saltLengthBytes() const { return m_saltLengthBytes; }
+
+private:
+    const unsigned m_saltLengthBytes;
+};
+
 } // namespace blink
 
 #endif