LibWeb: Always parse comma separated value lists as StyleValueList

Previously we would either parse these as `StyleValueList<T>` or `T`
depending on whether or not there was more than one value, this meant we
always had to handle both cases anywhere we used these values.

Author: Calme1709

Libraries/LibWeb/Animations/AnimationEffect.cpp

@@ -17,6 +17,7 @@
 #include <LibWeb/CSS/StyleComputer.h>
 #include <LibWeb/CSS/StyleInvalidation.h>
 #include <LibWeb/CSS/StyleValues/KeywordStyleValue.h>
+#include <LibWeb/CSS/StyleValues/StyleValueList.h>
 #include <LibWeb/DOM/Element.h>
 #include <LibWeb/Layout/Node.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
@@ -609,11 +610,16 @@ Optional<double> AnimationEffect::transformed_progress() const
 Optional<CSS::EasingFunction> AnimationEffect::parse_easing_string(StringView value)
 {
     if (auto style_value = parse_css_value(CSS::Parser::ParsingParams(), value, CSS::PropertyID::AnimationTimingFunction)) {
-        if (style_value->is_unresolved() || style_value->is_value_list() || style_value->is_css_wide_keyword())
+        if (style_value->is_unresolved() || style_value->is_css_wide_keyword())
             return {};
 
-        // FIXME: We should absolutize style_value to resolve relative lengths within calcs
-        return CSS::EasingFunction::from_style_value(style_value.release_nonnull());
+        auto easing_values = style_value->as_value_list().values();
+
+        if (easing_values.size() != 1)
+            return {};
+
+        // FIXME: We should absolutize the style value to resolve relative lengths within calcs
+        return CSS::EasingFunction::from_style_value(easing_values[0]);
     }
 
     return {};

Libraries/LibWeb/CSS/CSSStyleProperties.cpp

@@ -879,7 +879,7 @@ RefPtr<StyleValue const> CSSStyleProperties::style_value_for_computed_property(L
         auto const& animation_timeline_computed_value = get_computed_value(PropertyID::AnimationTimeline);
         auto const& animation_duration_computed_value = get_computed_value(PropertyID::AnimationDuration);
 
-        if (animation_timeline_computed_value.to_keyword() == Keyword::Auto) {
+        if (animation_timeline_computed_value.as_value_list().size() == 1 && animation_timeline_computed_value.as_value_list().values()[0]->to_keyword() == Keyword::Auto) {
 
             // FIXME: We can remove these two branches once parse_comma_separated_value_list always returns StyleValueList.
             if (animation_duration_computed_value.to_keyword() == Keyword::Auto)

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -448,8 +448,8 @@ class Parser {
     RefPtr<ViewFunctionStyleValue const> parse_view_function_value(TokenStream<ComponentValue>&);
 
     using ParseFunction = AK::Function<RefPtr<StyleValue const>(TokenStream<ComponentValue>&)>;
-    RefPtr<StyleValue const> parse_comma_separated_value_list(TokenStream<ComponentValue>&, ParseFunction);
-    RefPtr<StyleValue const> parse_simple_comma_separated_value_list(PropertyID, TokenStream<ComponentValue>&);
+    RefPtr<StyleValueList const> parse_comma_separated_value_list(TokenStream<ComponentValue>&, ParseFunction);
+    RefPtr<StyleValueList const> parse_simple_comma_separated_value_list(PropertyID, TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_coordinating_value_list_shorthand(TokenStream<ComponentValue>&, PropertyID shorthand_id, Vector<PropertyID> const& longhand_ids, Vector<PropertyID> const& reset_only_longhand_ids);
     RefPtr<StyleValue const> parse_all_as_single_keyword_value(TokenStream<ComponentValue>&, Keyword);
 

Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp

@@ -88,7 +88,7 @@ RefPtr<StyleValue const> Parser::parse_all_as_single_keyword_value(TokenStream<C
     return keyword_value;
 }
 
-RefPtr<StyleValue const> Parser::parse_simple_comma_separated_value_list(PropertyID property_id, TokenStream<ComponentValue>& tokens)
+RefPtr<StyleValueList const> Parser::parse_simple_comma_separated_value_list(PropertyID property_id, TokenStream<ComponentValue>& tokens)
 {
     return parse_comma_separated_value_list(tokens, [this, property_id](auto& tokens) -> RefPtr<StyleValue const> {
         if (auto value = parse_css_value_for_property(property_id, tokens))
@@ -149,15 +149,8 @@ RefPtr<StyleValue const> Parser::parse_coordinating_value_list_shorthand(TokenSt
     longhand_ids_including_reset_only_longhands.extend(reset_only_longhand_ids);
     StyleValueVector longhand_values {};
 
-    // FIXME: This is for compatibility with parse_comma_separated_value_list(), which returns a single value directly
-    //        instead of a list if there's only one, it would be nicer if we always returned a list.
-    if (longhand_vectors.get(longhand_ids[0])->size() == 1) {
-        for (auto const& longhand_id : longhand_ids)
-            longhand_values.append((*longhand_vectors.get(longhand_id))[0]);
-    } else {
-        for (auto const& longhand_id : longhand_ids)
-            longhand_values.append(StyleValueList::create(move(*longhand_vectors.get(longhand_id)), StyleValueList::Separator::Comma));
-    }
+    for (auto const& longhand_id : longhand_ids)
+        longhand_values.append(StyleValueList::create(move(*longhand_vectors.get(longhand_id)), StyleValueList::Separator::Comma));
 
     for (auto reset_only_longhand_id : reset_only_longhand_ids)
         longhand_values.append(property_initial_value(reset_only_longhand_id));
@@ -5079,7 +5072,7 @@ RefPtr<StyleValue const> Parser::parse_transition_property_value(TokenStream<Com
 
     // none
     if (auto none = parse_all_as_single_keyword_value(tokens, Keyword::None))
-        return none;
+        return StyleValueList::create({ none.release_nonnull() }, StyleValueList::Separator::Comma);
 
     // <single-transition-property>#
     // <single-transition-property> = all | <custom-ident>

Libraries/LibWeb/CSS/Parser/ValueParsing.cpp

@@ -80,13 +80,13 @@
 
 namespace Web::CSS::Parser {
 
-RefPtr<StyleValue const> Parser::parse_comma_separated_value_list(TokenStream<ComponentValue>& tokens, ParseFunction parse_one_value)
+RefPtr<StyleValueList const> Parser::parse_comma_separated_value_list(TokenStream<ComponentValue>& tokens, ParseFunction parse_one_value)
 {
     tokens.discard_whitespace();
     auto first = parse_one_value(tokens);
     tokens.discard_whitespace();
-    if (!first || !tokens.has_next_token())
-        return first;
+    if (!first)
+        return nullptr;
 
     StyleValueVector values;
     values.append(first.release_nonnull());