LibWeb: Parse CSS "font-variant" as part of "font"

This allows us to parse CSS "font" values that contain e.g "small-caps"
or "normal", as used on Acid3.

Userland/Libraries/LibWeb/CSS/ComputedValues.h

@@ -16,6 +16,7 @@ class InitialValues {
 public:
     static float font_size() { return 10; }
     static int font_weight() { return 400; }
+    static CSS::FontVariant font_variant() { return CSS::FontVariant::Normal; }
     static CSS::Float float_() { return CSS::Float::None; }
     static CSS::Clear clear() { return CSS::Clear::None; }
     static CSS::Cursor cursor() { return CSS::Cursor::Auto; }
@@ -178,6 +179,7 @@ public:
 
     float font_size() const { return m_inherited.font_size; }
     int font_weight() const { return m_inherited.font_weight; }
+    CSS::FontVariant font_variant() const { return m_inherited.font_variant; }
 
     ComputedValues clone_inherited_values() const
     {
@@ -190,6 +192,7 @@ protected:
     struct {
         float font_size { InitialValues::font_size() };
         int font_weight { InitialValues::font_weight() };
+        CSS::FontVariant font_variant { InitialValues::font_variant() };
         Color color { InitialValues::color() };
         CSS::Cursor cursor { InitialValues::cursor() };
         CSS::ImageRendering image_rendering { InitialValues::image_rendering() };
@@ -261,6 +264,7 @@ class MutableComputedValues final : public ComputedValues {
 public:
     void set_font_size(float font_size) { m_inherited.font_size = font_size; }
     void set_font_weight(int font_weight) { m_inherited.font_weight = font_weight; }
+    void set_font_variant(CSS::FontVariant font_variant) { m_inherited.font_variant = font_variant; }
     void set_color(const Color& color) { m_inherited.color = color; }
     void set_content(ContentData const& content) { m_noninherited.content = content; }
     void set_cursor(CSS::Cursor cursor) { m_inherited.cursor = cursor; }

Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -3590,7 +3590,8 @@ RefPtr<StyleValue> Parser::parse_font_value(Vector<StyleComponentValueRule> cons
     RefPtr<StyleValue> font_size;
     RefPtr<StyleValue> line_height;
     RefPtr<StyleValue> font_families;
-    // FIXME: Implement font-stretch and font-variant.
+    RefPtr<StyleValue> font_variant;
+    // FIXME: Implement font-stretch.
 
     // FIXME: Handle system fonts. (caption, icon, menu, message-box, small-caption, status-bar)
 
@@ -3620,6 +3621,12 @@ RefPtr<StyleValue> Parser::parse_font_value(Vector<StyleComponentValueRule> cons
             font_weight = value.release_nonnull();
             continue;
         }
+        if (property_accepts_value(PropertyID::FontVariant, *value)) {
+            if (font_variant)
+                return nullptr;
+            font_variant = value.release_nonnull();
+            continue;
+        }
         if (property_accepts_value(PropertyID::FontSize, *value)) {
             if (font_size)
                 return nullptr;

Userland/Libraries/LibWeb/CSS/StyleProperties.cpp

@@ -999,4 +999,20 @@ Variant<CSS::VerticalAlign, CSS::LengthPercentage> StyleProperties::vertical_ali
     VERIFY_NOT_REACHED();
 }
 
+Optional<CSS::FontVariant> StyleProperties::font_variant() const
+{
+    auto value = property(CSS::PropertyID::FontVariant);
+    if (!value.has_value())
+        return {};
+
+    switch (value.value()->to_identifier()) {
+    case CSS::ValueID::Normal:
+        return CSS::FontVariant::Normal;
+    case CSS::ValueID::SmallCaps:
+        return CSS::FontVariant::SmallCaps;
+    default:
+        return {};
+    }
+}
+
 }

Userland/Libraries/LibWeb/CSS/StyleProperties.h

@@ -75,6 +75,7 @@ public:
     CSS::BoxSizing box_sizing() const;
     Optional<CSS::PointerEvents> pointer_events() const;
     Variant<CSS::VerticalAlign, CSS::LengthPercentage> vertical_align() const;
+    Optional<CSS::FontVariant> font_variant() const;
 
     Vector<CSS::Transformation> transformations() const;
     CSS::TransformOrigin transform_origin() const;

Userland/Libraries/LibWeb/CSS/StyleValue.h

@@ -146,6 +146,11 @@ enum class Float {
     Right,
 };
 
+enum class FontVariant {
+    Normal,
+    SmallCaps,
+};
+
 enum class ImageRendering {
     Auto,
     CrispEdges,

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -363,6 +363,9 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& specified_style)
     computed_values.set_font_size(specified_style.property(CSS::PropertyID::FontSize).value()->to_length().to_px(*this));
     computed_values.set_font_weight(specified_style.property(CSS::PropertyID::FontWeight).value()->to_integer());
 
+    if (auto maybe_font_variant = specified_style.font_variant(); maybe_font_variant.has_value())
+        computed_values.set_font_variant(maybe_font_variant.release_value());
+
     // FIXME: BorderXRadius properties are now BorderRadiusStyleValues, so make use of that.
     auto border_bottom_left_radius = specified_style.property(CSS::PropertyID::BorderBottomLeftRadius);
     if (border_bottom_left_radius.has_value() && border_bottom_left_radius.value()->is_border_radius())