LibWeb/CSS: Return GC::Ref from style sheet parsing methods

These actually always return a value, despite the `CSSStyleSheet*`
return type. So, make that clearer by returning `GC::Ref<CSSStyleSheet>`
instead. This also means we can remove some ad-hoc error-checking code.

Libraries/LibWeb/CSS/CSSImportRule.cpp

@@ -156,7 +156,7 @@ void CSSImportRule::fetch()
             }
             auto decoded = decoded_or_error.release_value();
 
-            auto* imported_style_sheet = parse_css_stylesheet(Parser::ParsingParams(*strong_this->m_document, parsed_url), decoded, parsed_url, strong_this->m_media_query_list);
+            auto imported_style_sheet = parse_css_stylesheet(Parser::ParsingParams(*strong_this->m_document, parsed_url), decoded, parsed_url, strong_this->m_media_query_list);
 
             // 5. Set importedStylesheet’s origin-clean flag to parentStylesheet’s origin-clean flag.
             imported_style_sheet->set_origin_clean(parent_style_sheet->is_origin_clean());
@@ -166,7 +166,7 @@ void CSSImportRule::fetch()
                 imported_style_sheet->set_origin_clean(false);
 
             // 7. Set rule’s styleSheet to importedStylesheet.
-            strong_this->set_style_sheet(*imported_style_sheet);
+            strong_this->set_style_sheet(imported_style_sheet);
         });
 }
 

Libraries/LibWeb/CSS/CSSStyleSheet.cpp

@@ -207,7 +207,7 @@ GC::Ref<WebIDL::Promise> CSSStyleSheet::replace(String text)
         HTML::TemporaryExecutionContext execution_context { realm, HTML::TemporaryExecutionContext::CallbacksEnabled::Yes };
 
         // 1. Let rules be the result of running parse a stylesheet’s contents from text.
-        auto* parsed_stylesheet = parse_css_stylesheet(make_parsing_params(), text);
+        auto parsed_stylesheet = parse_css_stylesheet(make_parsing_params(), text);
         auto& rules = parsed_stylesheet->rules();
 
         // 2. If rules contains one or more @import rules, remove those rules from rules.
@@ -240,7 +240,7 @@ WebIDL::ExceptionOr<void> CSSStyleSheet::replace_sync(StringView text)
         return WebIDL::NotAllowedError::create(realm(), "Can't call replaceSync() on non-modifiable stylesheets"_string);
 
     // 2. Let rules be the result of running parse a stylesheet’s contents from text.
-    auto* parsed_stylesheet = parse_css_stylesheet(make_parsing_params(), text);
+    auto parsed_stylesheet = parse_css_stylesheet(make_parsing_params(), text);
     auto& rules = parsed_stylesheet->rules();
 
     // 3. If rules contains one or more @import rules, remove those rules from rules.

Libraries/LibWeb/CSS/Parser/Helpers.cpp

@@ -42,7 +42,7 @@ GC::Ref<JS::Realm> internal_css_realm()
     return *realm;
 }
 
-CSS::CSSStyleSheet* parse_css_stylesheet(CSS::Parser::ParsingParams const& context, StringView css, Optional<::URL::URL> location, Vector<NonnullRefPtr<CSS::MediaQuery>> media_query_list)
+GC::Ref<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::Parser::ParsingParams const& context, StringView css, Optional<::URL::URL> location, Vector<NonnullRefPtr<CSS::MediaQuery>> media_query_list)
 {
     if (css.is_empty()) {
         auto rule_list = CSS::CSSRuleList::create_empty(*context.realm);
@@ -51,7 +51,7 @@ CSS::CSSStyleSheet* parse_css_stylesheet(CSS::Parser::ParsingParams const& conte
         style_sheet->set_source_text({});
         return style_sheet;
     }
-    auto* style_sheet = CSS::Parser::Parser::create(context, css).parse_as_css_stylesheet(location, move(media_query_list));
+    auto style_sheet = CSS::Parser::Parser::create(context, css).parse_as_css_stylesheet(location, move(media_query_list));
     // FIXME: Avoid this copy
     style_sheet->set_source_text(MUST(String::from_utf8(css)));
     return style_sheet;

Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -119,7 +119,7 @@ Vector<Rule> Parser::parse_a_stylesheets_contents(TokenStream<T>& input)
 }
 
 // https://drafts.csswg.org/css-syntax/#parse-a-css-stylesheet
-CSSStyleSheet* Parser::parse_as_css_stylesheet(Optional<::URL::URL> location, Vector<NonnullRefPtr<MediaQuery>> media_query_list)
+GC::Ref<CSS::CSSStyleSheet> Parser::parse_as_css_stylesheet(Optional<::URL::URL> location, Vector<NonnullRefPtr<MediaQuery>> media_query_list)
 {
     // To parse a CSS stylesheet, first parse a stylesheet.
     auto const& style_sheet = parse_a_stylesheet(m_token_stream, location);

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -90,7 +90,7 @@ class Parser {
 public:
     static Parser create(ParsingParams const&, StringView input, StringView encoding = "utf-8"sv);
 
-    CSSStyleSheet* parse_as_css_stylesheet(Optional<::URL::URL> location, Vector<NonnullRefPtr<MediaQuery>> media_query_list = {});
+    GC::Ref<CSS::CSSStyleSheet> parse_as_css_stylesheet(Optional<::URL::URL> location, Vector<NonnullRefPtr<MediaQuery>> media_query_list = {});
 
     struct PropertiesAndCustomProperties {
         Vector<StyleProperty> properties;
@@ -520,7 +520,7 @@ private:
 
 namespace Web {
 
-CSS::CSSStyleSheet* parse_css_stylesheet(CSS::Parser::ParsingParams const&, StringView, Optional<::URL::URL> location = {}, Vector<NonnullRefPtr<CSS::MediaQuery>> = {});
+GC::Ref<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::Parser::ParsingParams const&, StringView, Optional<::URL::URL> location = {}, Vector<NonnullRefPtr<CSS::MediaQuery>> = {});
 CSS::Parser::Parser::PropertiesAndCustomProperties parse_css_style_attribute(CSS::Parser::ParsingParams const&, StringView);
 Vector<CSS::Descriptor> parse_css_list_of_descriptors(CSS::Parser::ParsingParams const&, CSS::AtRuleID, StringView);
 RefPtr<CSS::CSSStyleValue> parse_css_value(CSS::Parser::ParsingParams const&, StringView, CSS::PropertyID property_id = CSS::PropertyID::Invalid);

Libraries/LibWeb/CSS/StyleSheetList.cpp

@@ -61,20 +61,13 @@ void StyleSheetList::add_a_css_style_sheet(CSS::CSSStyleSheet& sheet)
 }
 
 // https://www.w3.org/TR/cssom/#create-a-css-style-sheet
-GC::Ptr<CSSStyleSheet> StyleSheetList::create_a_css_style_sheet(String const& css_text, String type, DOM::Element* owner_node, String media, String title, Alternate alternate, OriginClean origin_clean, Optional<::URL::URL> location, CSSStyleSheet* parent_style_sheet, CSSRule* owner_rule)
+GC::Ref<CSSStyleSheet> StyleSheetList::create_a_css_style_sheet(String const& css_text, String type, DOM::Element* owner_node, String media, String title, Alternate alternate, OriginClean origin_clean, Optional<::URL::URL> location, CSSStyleSheet* parent_style_sheet, CSSRule* owner_rule)
 {
     // 1. Create a new CSS style sheet object and set its properties as specified.
     // AD-HOC: The spec never tells us when to parse this style sheet, but the most logical place is here.
     // AD-HOC: Are we supposed to use the document's URL for the stylesheet's location during parsing? Not doing it breaks things.
     auto location_url = location.value_or(document().url());
-    auto* sheet = parse_css_stylesheet(Parser::ParsingParams { document(), location_url }, css_text, location_url);
+    auto sheet = parse_css_stylesheet(Parser::ParsingParams { document(), location_url }, css_text, location_url);
-
-    // AD-HOC: Exit out if parsing failed.
-    // FIXME: What should we actually do here?
-    if (!sheet) {
-        dbgln_if(CSS_LOADER_DEBUG, "StyleSheetList::create_a_css_style_sheet(): Failed to parse stylesheet at {}", location_url);
-        return nullptr;
-    }
 
     sheet->set_parent_css_style_sheet(parent_style_sheet);
     sheet->set_owner_css_rule(owner_rule);

Libraries/LibWeb/CSS/StyleSheetList.h

@@ -30,7 +30,7 @@ public:
         No,
         Yes,
     };
-    GC::Ptr<CSSStyleSheet> create_a_css_style_sheet(String const& css_text, String type, DOM::Element* owner_node, String media, String title, Alternate, OriginClean, Optional<::URL::URL> location, CSSStyleSheet* parent_style_sheet, CSSRule* owner_rule);
+    GC::Ref<CSSStyleSheet> create_a_css_style_sheet(String const& css_text, String type, DOM::Element* owner_node, String media, String title, Alternate, OriginClean, Optional<::URL::URL> location, CSSStyleSheet* parent_style_sheet, CSSRule* owner_rule);
 
     Vector<GC::Ref<CSSStyleSheet>> const& sheets() const { return m_sheets; }
     Vector<GC::Ref<CSSStyleSheet>>& sheets() { return m_sheets; }