LibWeb: Parse corner-*-shape physical longhands

Author: https://github.com/Calme1709
Commit: 814efa9809
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6425
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/CSS/StyleValues/SuperellipseStyleValue.cpp

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2025, Callum Law <callumlaw1709@outlook.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "SuperellipseStyleValue.h"
+#include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
+
+namespace Web::CSS {
+
+String SuperellipseStyleValue::to_string(SerializationMode mode) const
+{
+    auto stringified_parameter = [&] {
+        if (!m_parameter->is_number())
+            return m_parameter->to_string(mode);
+
+        auto number = m_parameter->as_number().number();
+
+        if (number == AK::Infinity<double>)
+            return "infinity"_string;
+
+        if (number == -AK::Infinity<double>)
+            return "-infinity"_string;
+
+        return m_parameter->to_string(mode);
+    }();
+
+    return MUST(String::formatted("superellipse({})", stringified_parameter));
+}
+
+}