LibWeb: Implement details_notification_task_steps for <details>

Userland/Libraries/LibWeb/DOM/Element.h

@@ -89,11 +89,11 @@ public:
     bool has_attributes() const;
     DeprecatedString attribute(DeprecatedFlyString const& name) const { return get_attribute(name); }
     DeprecatedString get_attribute(DeprecatedFlyString const& name) const;
-    WebIDL::ExceptionOr<void> set_attribute(DeprecatedFlyString const& name, DeprecatedString const& value);
+    virtual WebIDL::ExceptionOr<void> set_attribute(DeprecatedFlyString const& name, DeprecatedString const& value);
     WebIDL::ExceptionOr<void> set_attribute_ns(DeprecatedFlyString const& namespace_, DeprecatedFlyString const& qualified_name, DeprecatedString const& value);
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_attribute_node(Attr&);
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_attribute_node_ns(Attr&);
-    void remove_attribute(DeprecatedFlyString const& name);
+    virtual void remove_attribute(DeprecatedFlyString const& name);
     WebIDL::ExceptionOr<bool> toggle_attribute(DeprecatedFlyString const& name, Optional<bool> force);
     size_t attribute_list_size() const;
     NamedNodeMap const* attributes() const { return m_attributes.ptr(); }

Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.cpp

@@ -5,7 +5,9 @@
  */
 
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/DOM/Event.h>
 #include <LibWeb/HTML/HTMLDetailsElement.h>
+#include <LibWeb/HTML/HTMLSummaryElement.h>
 
 namespace Web::HTML {
 
@@ -16,6 +18,40 @@ HTMLDetailsElement::HTMLDetailsElement(DOM::Document& document, DOM::QualifiedNa
 
 HTMLDetailsElement::~HTMLDetailsElement() = default;
 
+WebIDL::ExceptionOr<void> HTMLDetailsElement::set_attribute(DeprecatedFlyString const& name, DeprecatedString const& value)
+{
+    auto result = HTMLElement::set_attribute(name, value);
+    if (result.is_exception())
+        return result.exception();
+
+    if (name == HTML::AttributeNames::open)
+        run_details_notification_task_steps();
+
+    return result;
+}
+
+void HTMLDetailsElement::remove_attribute(DeprecatedFlyString const& name)
+{
+    HTMLElement::remove_attribute(name);
+
+    if (name == HTML::AttributeNames::open)
+        run_details_notification_task_steps();
+}
+
+// https://html.spec.whatwg.org/multipage/interactive-elements.html#the-details-element:details-notification-task-steps
+void HTMLDetailsElement::run_details_notification_task_steps()
+{
+    // Whenever the open attribute is added to or removed from a details element,
+    // the user agent must queue an element task on the DOM manipulation task source given then details element that runs the following steps,
+    // which are known as the details notification task steps, for this details element:
+    queue_an_element_task(HTML::Task::Source::DOMManipulation, [this] {
+        // 1. FIXME: If another task has been queued to run the details notification task steps for this details element, then return.
+
+        // 2. Fire an event named toggle at the details element.
+        dispatch_event(Web::DOM::Event::create(realm(), HTML::EventNames::toggle).release_value_but_fixme_should_propagate_errors());
+    });
+}
+
 JS::ThrowCompletionOr<void> HTMLDetailsElement::initialize(JS::Realm& realm)
 {
     MUST_OR_THROW_OOM(Base::initialize(realm));

Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.h

@@ -20,6 +20,12 @@ public:
     // https://www.w3.org/TR/html-aria/#el-details
     virtual Optional<ARIA::Role> default_role() const override { return ARIA::Role::group; };
 
+    // ^Element
+    WebIDL::ExceptionOr<void> set_attribute(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    void remove_attribute(DeprecatedFlyString const& name) override;
+
+    void run_details_notification_task_steps();
+
 private:
     HTMLDetailsElement(DOM::Document&, DOM::QualifiedName);