LibWeb/CSS: Remove illegal <number-percentage> type

Various places in the spec allow for `<number> | <percentage>`, but this
is either/or, and they are not allowed to be combined like dimensions
and percentages are. (For example, `calc(12 + 50%)` is never valid.)

User code generally doesn't need to care about this distinction, but it
does now need to check if a calculation resolves to a number, or to a
percentage, instead of a single call.

The existing parse_number_percentage[_value]() methods have been kept
for simplicity, but updated to check for number/percentage separately.

Libraries/LibWeb/CSS/CSSNumericType.cpp

@@ -446,14 +446,6 @@ bool CSSNumericType::matches_number() const
     return true;
 }
 
-// https://drafts.css-houdini.org/css-typed-om-1/#cssnumericvalue-match
-bool CSSNumericType::matches_number_percentage() const
-{
-    // FIXME: This is incorrect. <number-percentage> is not a legal type. Instead we should check separately if this
-    //        matches a number, or if it matches a percentage.
-    return matches_number() || matches_percentage();
-}
-
 bool CSSNumericType::matches_dimension() const
 {
     // This isn't a spec algorithm.

Libraries/LibWeb/CSS/CSSNumericType.h

@@ -76,7 +76,6 @@ class CSSNumericType {
     bool matches_length() const { return matches_dimension(BaseType::Length); }
     bool matches_length_percentage() const { return matches_dimension_percentage(BaseType::Length); }
     bool matches_number() const;
-    bool matches_number_percentage() const;
     bool matches_percentage() const;
     bool matches_resolution() const { return matches_dimension(BaseType::Resolution); }
     bool matches_resolution_percentage() const { return matches_dimension_percentage(BaseType::Resolution); }

Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -2489,45 +2489,24 @@ RefPtr<CSSStyleValue> Parser::parse_number_value(TokenStream<ComponentValue>& to
 RefPtr<CSSStyleValue> Parser::parse_number_percentage_value(TokenStream<ComponentValue>& tokens)
 {
     // Parses [<percentage> | <number>] (which is equivalent to [<alpha-value>])
-    auto const& peek_token = tokens.next_token();
-    if (peek_token.is(Token::Type::Number)) {
-        tokens.discard_a_token(); // number
-        return NumberStyleValue::create(peek_token.token().number().value());
-    }
-    if (peek_token.is(Token::Type::Percentage)) {
-        tokens.discard_a_token(); // percentage
-        return PercentageStyleValue::create(Percentage(peek_token.token().percentage()));
-    }
-    if (auto calc = parse_calculated_value(peek_token); calc && calc->resolves_to_number_percentage()) {
-        tokens.discard_a_token(); // calc
-        return calc;
-    }
-
+    if (auto value = parse_number_value(tokens))
+        return value;
+    if (auto value = parse_percentage_value(tokens))
+        return value;
     return nullptr;
 }
 
 RefPtr<CSSStyleValue> Parser::parse_number_percentage_none_value(TokenStream<ComponentValue>& tokens)
 {
     // Parses [<percentage> | <number> | none] (which is equivalent to [<alpha-value> | none])
-    auto peek_token = tokens.next_token();
-    if (peek_token.is(Token::Type::Number)) {
-        tokens.discard_a_token(); // number
-        return NumberStyleValue::create(peek_token.token().number().value());
-    }
-    if (peek_token.is(Token::Type::Percentage)) {
-        tokens.discard_a_token(); // percentage
-        return PercentageStyleValue::create(Percentage(peek_token.token().percentage()));
-    }
-    if (auto calc = parse_calculated_value(peek_token); calc && calc->resolves_to_number_percentage()) {
-        tokens.discard_a_token(); // calc
-        return calc;
-    }
-    if (peek_token.is(Token::Type::Ident)) {
-        auto keyword = keyword_from_string(peek_token.token().ident());
-        if (keyword.has_value() && keyword.value() == Keyword::None) {
-            tokens.discard_a_token(); // keyword none
-            return CSSKeywordValue::create(keyword.value());
-        }
+    if (auto value = parse_number_value(tokens))
+        return value;
+    if (auto value = parse_percentage_value(tokens))
+        return value;
+
+    if (tokens.next_token().is_ident("none"sv)) {
+        tokens.discard_a_token(); // keyword none
+        return CSSKeywordValue::create(Keyword::None);
     }
 
     return nullptr;

Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h

@@ -99,7 +99,6 @@ class CalculatedStyleValue : public CSSStyleValue {
     Optional<Time> resolve_time_percentage(Time const& percentage_basis) const;
 
     bool resolves_to_number() const { return m_resolved_type.matches_number(); }
-    bool resolves_to_number_percentage() const { return m_resolved_type.matches_number_percentage(); }
     Optional<double> resolve_number() const;
     Optional<double> resolve_number(Length::ResolutionContext const&) const;
     Optional<double> resolve_number(Layout::Node const& layout_node) const;