LibWeb: Split StringStyleValue out of StyleValue.{h,cpp}

Author: https://github.com/AtkinsSJ
Commit: https://github.com/SerenityOS/serenity/commit/9b834058ee
Pull-request: https://github.com/SerenityOS/serenity/pull/18040

Userland/Libraries/LibWeb/CSS/StyleValues/StringStyleValue.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2022-2023, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/String.h>
+#include <LibWeb/CSS/StyleValue.h>
+
+namespace Web::CSS {
+
+class StringStyleValue : public StyleValueWithDefaultOperators<StringStyleValue> {
+public:
+    static ValueComparingNonnullRefPtr<StringStyleValue> create(String const& string)
+    {
+        return adopt_ref(*new StringStyleValue(string));
+    }
+    virtual ~StringStyleValue() override = default;
+
+    ErrorOr<String> to_string() const override { return m_string; }
+
+    bool properties_equal(StringStyleValue const& other) const { return m_string == other.m_string; }
+
+private:
+    explicit StringStyleValue(String const& string)
+        : StyleValueWithDefaultOperators(Type::String)
+        , m_string(string)
+    {
+    }
+
+    String m_string;
+};
+
+}