LibWeb: Allow multiple values for transition-timing-function property

Author: https://github.com/tcl3
Commit: c5f1f36119
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4387
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp

@@ -674,6 +674,10 @@ Parser::ParseErrorOr<NonnullRefPtr<CSSStyleValue const>> Parser::parse_css_value
         if (auto parsed_value = parse_transition_property_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();
         return ParseError::SyntaxError;
+    case PropertyID::TransitionTimingFunction:
+        if (auto parsed_value = parse_comma_separated_value_list(tokens, [this](auto& tokens) { return parse_easing_value(tokens); }))
+            return parsed_value.release_nonnull();
+        return ParseError::SyntaxError;
     case PropertyID::Translate:
         if (auto parsed_value = parse_translate_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();