LibWeb: Store Repeat values directly in BackgroundRepeatStyleValue

...as opposed to storing StyleValues, which we have to later check are
IdentifierStyleValues, which store identifiers that we can convert to
Repeat values later. It's fewer allocations, and we can't end up with
invalid values by mistake. :^)

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

@@ -2702,6 +2702,21 @@ RefPtr<StyleValue> Parser::parse_single_background_repeat_value(ParsingContext c
         return value_id == ValueID::RepeatX || value_id == ValueID::RepeatY;
     };
 
+    auto as_repeat = [](ValueID identifier) {
+        switch (identifier) {
+        case ValueID::NoRepeat:
+            return Repeat::NoRepeat;
+        case ValueID::Repeat:
+            return Repeat::Repeat;
+        case ValueID::Round:
+            return Repeat::Round;
+        case ValueID::Space:
+            return Repeat::Space;
+        default:
+            VERIFY_NOT_REACHED();
+        }
+    };
+
     auto& token = tokens.next_token();
     auto maybe_x_value = parse_css_value(context, token);
     if (!maybe_x_value || !property_accepts_value(PropertyID::BackgroundRepeat, *maybe_x_value))
@@ -2711,8 +2726,8 @@ RefPtr<StyleValue> Parser::parse_single_background_repeat_value(ParsingContext c
     if (is_directional_repeat(*x_value)) {
         auto value_id = x_value->to_identifier();
         return BackgroundRepeatStyleValue::create(
-            IdentifierStyleValue::create(value_id == ValueID::RepeatX ? ValueID::Repeat : ValueID::NoRepeat),
+            value_id == ValueID::RepeatX ? Repeat::Repeat : Repeat::NoRepeat,
-            IdentifierStyleValue::create(value_id == ValueID::RepeatX ? ValueID::NoRepeat : ValueID::Repeat));
+            value_id == ValueID::RepeatX ? Repeat::NoRepeat : Repeat::Repeat);
     }
 
     // See if we have a second value for Y
@@ -2720,13 +2735,13 @@ RefPtr<StyleValue> Parser::parse_single_background_repeat_value(ParsingContext c
     auto maybe_y_value = parse_css_value(context, second_token);
     if (!maybe_y_value || !property_accepts_value(PropertyID::BackgroundRepeat, *maybe_y_value)) {
         // We don't have a second value, so use x for both
-        return BackgroundRepeatStyleValue::create(x_value, x_value);
+        return BackgroundRepeatStyleValue::create(as_repeat(x_value->to_identifier()), as_repeat(x_value->to_identifier()));
     }
     tokens.next_token();
     auto y_value = maybe_y_value.release_nonnull();
     if (is_directional_repeat(*y_value))
         return error();
-    return BackgroundRepeatStyleValue::create(x_value, y_value);
+    return BackgroundRepeatStyleValue::create(as_repeat(x_value->to_identifier()), as_repeat(y_value->to_identifier()));
 }
 
 RefPtr<StyleValue> Parser::parse_background_repeat_value(ParsingContext const& context, Vector<StyleComponentValueRule> const& component_values)

Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp

@@ -374,21 +374,6 @@ static CSS::ValueID to_css_value_id(CSS::Overflow value)
     VERIFY_NOT_REACHED();
 }
 
-static CSS::ValueID to_css_value_id(CSS::Repeat value)
-{
-    switch (value) {
-    case Repeat::NoRepeat:
-        return CSS::ValueID::NoRepeat;
-    case Repeat::Repeat:
-        return CSS::ValueID::Repeat;
-    case Repeat::Round:
-        return CSS::ValueID::Round;
-    case Repeat::Space:
-        return CSS::ValueID::Space;
-    }
-    VERIFY_NOT_REACHED();
-}
-
 static CSS::ValueID to_css_value_id(CSS::ListStyleType value)
 {
     switch (value) {
@@ -662,8 +647,8 @@ RefPtr<StyleValue> ResolvedCSSStyleDeclaration::style_value_for_property(Layout:
         return ColorStyleValue::create(layout_node.computed_values().background_color());
     case CSS::PropertyID::BackgroundRepeat:
         return BackgroundRepeatStyleValue::create(
-            IdentifierStyleValue::create(to_css_value_id(layout_node.computed_values().background_repeat().repeat_x)),
+            layout_node.computed_values().background_repeat().repeat_x,
-            IdentifierStyleValue::create(to_css_value_id(layout_node.computed_values().background_repeat().repeat_y)));
+            layout_node.computed_values().background_repeat().repeat_y);
     case CSS::PropertyID::Background: {
         auto maybe_background_color = property(CSS::PropertyID::BackgroundColor);
         auto maybe_background_image = property(CSS::PropertyID::BackgroundImage);
@@ -677,7 +662,7 @@ RefPtr<StyleValue> ResolvedCSSStyleDeclaration::style_value_for_property(Layout:
             value_or_default(maybe_background_color, InitialStyleValue::the()),
             value_or_default(maybe_background_image, IdentifierStyleValue::create(CSS::ValueID::None)),
             value_or_default(maybe_background_position, PositionStyleValue::create(PositionEdge::Left, Length::make_px(0), PositionEdge::Top, Length::make_px(0))),
-            value_or_default(maybe_background_repeat, BackgroundRepeatStyleValue::create(IdentifierStyleValue::create(CSS::ValueID::Repeat), IdentifierStyleValue::create(CSS::ValueID::Repeat))),
+            value_or_default(maybe_background_repeat, BackgroundRepeatStyleValue::create(CSS::Repeat::Repeat, CSS::Repeat::Repeat)),
             value_or_default(maybe_background_attachment, IdentifierStyleValue::create(CSS::ValueID::Scroll)),
             value_or_default(maybe_background_origin, IdentifierStyleValue::create(CSS::ValueID::PaddingBox)),
             value_or_default(maybe_background_clip, IdentifierStyleValue::create(CSS::ValueID::BorderBox)));

Userland/Libraries/LibWeb/CSS/StyleProperties.cpp

@@ -693,28 +693,9 @@ Optional<BackgroundRepeatData> StyleProperties::background_repeat() const
     auto value = property(CSS::PropertyID::BackgroundRepeat);
     if (!value.has_value() || !value.value()->is_background_repeat())
         return {};
+
     auto& background_repeat = value.value()->as_background_repeat();
-
+    return BackgroundRepeatData { background_repeat.repeat_x(), background_repeat.repeat_y() };
-    auto to_repeat = [](auto value) -> Optional<CSS::Repeat> {
-        switch (value->to_identifier()) {
-        case CSS::ValueID::NoRepeat:
-            return CSS::Repeat::NoRepeat;
-        case CSS::ValueID::Repeat:
-            return CSS::Repeat::Repeat;
-        case CSS::ValueID::Round:
-            return CSS::Repeat::Round;
-        case CSS::ValueID::Space:
-            return CSS::Repeat::Space;
-        default:
-            return {};
-        }
-    };
-    auto repeat_x = to_repeat(background_repeat.repeat_x());
-    auto repeat_y = to_repeat(background_repeat.repeat_y());
-    if (repeat_x.has_value() && repeat_y.has_value())
-        return BackgroundRepeatData { repeat_x.value(), repeat_y.value() };
-
-    return {};
 }
 
 Optional<CSS::BoxShadowData> StyleProperties::box_shadow() const

Userland/Libraries/LibWeb/CSS/StyleValue.h

@@ -181,6 +181,22 @@ enum class Repeat : u8 {
     Space,
 };
 
+constexpr StringView to_string(Repeat value)
+{
+    switch (value) {
+    case Repeat::NoRepeat:
+        return "no-repeat"sv;
+    case Repeat::Repeat:
+        return "repeat"sv;
+    case Repeat::Round:
+        return "round"sv;
+    case Repeat::Space:
+        return "space"sv;
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
 enum class TextAlign {
     Left,
     Center,
@@ -462,30 +478,30 @@ private:
 
 class BackgroundRepeatStyleValue final : public StyleValue {
 public:
-    static NonnullRefPtr<BackgroundRepeatStyleValue> create(NonnullRefPtr<StyleValue> repeat_x, NonnullRefPtr<StyleValue> repeat_y)
+    static NonnullRefPtr<BackgroundRepeatStyleValue> create(Repeat repeat_x, Repeat repeat_y)
     {
         return adopt_ref(*new BackgroundRepeatStyleValue(repeat_x, repeat_y));
     }
     virtual ~BackgroundRepeatStyleValue() override { }
 
-    NonnullRefPtr<StyleValue> repeat_x() const { return m_repeat_x; }
+    Repeat repeat_x() const { return m_repeat_x; }
-    NonnullRefPtr<StyleValue> repeat_y() const { return m_repeat_y; }
+    Repeat repeat_y() const { return m_repeat_y; }
 
     virtual String to_string() const override
     {
-        return String::formatted("{} {}", m_repeat_x->to_string(), m_repeat_y->to_string());
+        return String::formatted("{} {}", CSS::to_string(m_repeat_x), CSS::to_string(m_repeat_y));
     }
 
 private:
-    BackgroundRepeatStyleValue(NonnullRefPtr<StyleValue> repeat_x, NonnullRefPtr<StyleValue> repeat_y)
+    BackgroundRepeatStyleValue(Repeat repeat_x, Repeat repeat_y)
         : StyleValue(Type::BackgroundRepeat)
         , m_repeat_x(repeat_x)
         , m_repeat_y(repeat_y)
     {
     }
 
-    NonnullRefPtr<StyleValue> m_repeat_x;
+    Repeat m_repeat_x;
-    NonnullRefPtr<StyleValue> m_repeat_y;
+    Repeat m_repeat_y;
 };
 
 class BorderStyleValue final : public StyleValue {