LibWeb: Use IdentifierStyleValue for CSS 'text-decoration-line'

Also 'text-decoration' is actually a shorthand, so treat it that way.

Libraries/LibWeb/CSS/Parser/CSSParser.cpp

@@ -446,6 +446,14 @@ static Optional<CSS::ValueID> value_id_from_string(const String& string)
         return CSS::ValueID::TableHeaderGroup;
     if (string.equals_ignoring_case("table-footer-group"))
         return CSS::ValueID::TableFooterGroup;
+    if (string.equals_ignoring_case("underline"))
+        return CSS::ValueID::Underline;
+    if (string.equals_ignoring_case("overline"))
+        return CSS::ValueID::Overline;
+    if (string.equals_ignoring_case("line-through"))
+        return CSS::ValueID::LineThrough;
+    if (string.equals_ignoring_case("blink"))
+        return CSS::ValueID::Blink;
     if (string.starts_with("-libweb-palette-", CaseSensitivity::CaseInsensitive))
         return value_id_for_palette_string(string.substring_view(16, string.length() - 16));
     return {};

Libraries/LibWeb/CSS/Properties.json

@@ -304,6 +304,28 @@
     "initial": "left"
   },
   "text-decoration": {
+    "inherited": false,
+    "initial": "none",
+    "longhands": [
+      "text-decoration-color",
+      "text-decoration-line",
+      "text-decoration-style",
+      "text-decoration-thickness"
+    ]
+  },
+  "text-decoration-color": {
+    "inherited": false,
+    "initial": "none"
+  },
+  "text-decoration-line": {
+    "inherited": false,
+    "initial": "none"
+  },
+  "text-decoration-style": {
+    "inherited": false,
+    "initial": "none"
+  },
+  "text-decoration-thickness": {
     "inherited": false,
     "initial": "none"
   },

Libraries/LibWeb/CSS/StyleProperties.cpp

@@ -409,4 +409,25 @@ CSS::Display StyleProperties::display() const
     }
 }
 
+Optional<CSS::TextDecorationLine> StyleProperties::text_decoration_line() const
+{
+    auto value = property(CSS::PropertyID::TextDecorationLine);
+    if (!value.has_value() || !value.value()->is_identifier())
+        return {};
+    switch (static_cast<const IdentifierStyleValue&>(*value.value()).id()) {
+    case CSS::ValueID::None:
+        return CSS::TextDecorationLine::None;
+    case CSS::ValueID::Underline:
+        return CSS::TextDecorationLine::Underline;
+    case CSS::ValueID::Overline:
+        return CSS::TextDecorationLine::Overline;
+    case CSS::ValueID::LineThrough:
+        return CSS::TextDecorationLine::LineThrough;
+    case CSS::ValueID::Blink:
+        return CSS::TextDecorationLine::Blink;
+    default:
+        return {};
+    }
+}
+
 }

Libraries/LibWeb/CSS/StyleProperties.h

@@ -66,6 +66,7 @@ public:
     Optional<CSS::Clear> clear() const;
     Optional<CSS::WhiteSpace> white_space() const;
     Optional<CSS::LineStyle> line_style(CSS::PropertyID) const;
+    Optional<CSS::TextDecorationLine> text_decoration_line() const;
 
     const Gfx::Font& font() const
     {

Libraries/LibWeb/CSS/StyleResolver.cpp

@@ -229,6 +229,20 @@ static void set_property_expanding_shorthands(StyleProperties& style, CSS::Prope
 {
     CSS::ParsingContext context(document);
 
+    if (property_id == CSS::PropertyID::TextDecoration) {
+        switch (value.to_identifier()) {
+        case CSS::ValueID::None:
+        case CSS::ValueID::Underline:
+        case CSS::ValueID::Overline:
+        case CSS::ValueID::LineThrough:
+        case CSS::ValueID::Blink:
+            set_property_expanding_shorthands(style, CSS::PropertyID::TextDecorationLine, value, document);
+        default:
+            break;
+        }
+        return;
+    }
+
     if (property_id == CSS::PropertyID::Border) {
         set_property_expanding_shorthands(style, CSS::PropertyID::BorderTop, value, document);
         set_property_expanding_shorthands(style, CSS::PropertyID::BorderRight, value, document);

Libraries/LibWeb/CSS/StyleValue.h

@@ -147,6 +147,10 @@ enum class ValueID {
     TableHeaderGroup,
     TableRowGroup,
     TableFooterGroup,
+    Underline,
+    Overline,
+    LineThrough,
+    Blink,
 };
 
 enum class Position {
@@ -165,6 +169,14 @@ enum class TextAlign {
     VendorSpecificCenter,
 };
 
+enum class TextDecorationLine {
+    None,
+    Underline,
+    Overline,
+    LineThrough,
+    Blink,
+};
+
 enum class Display {
     None,
     Block,
@@ -244,6 +256,8 @@ public:
     virtual Length to_length() const { return Length::make_auto(); }
     virtual Color to_color(const DOM::Document&) const { return {}; }
 
+    CSS::ValueID to_identifier() const;
+
     virtual bool is_auto() const { return false; }
 
     bool operator==(const StyleValue& other) const { return equals(other); }
@@ -410,4 +424,11 @@ private:
     RefPtr<Gfx::Bitmap> m_bitmap;
 };
 
+inline CSS::ValueID StyleValue::to_identifier() const
+{
+    if (is_identifier())
+        return static_cast<const IdentifierStyleValue&>(*this).id();
+    return CSS::ValueID::Invalid;
+}
+
 }