LibWeb: Add activeElement attribute in ShadowRoot

Author: https://github.com/F3n67u
Commit: 66d18170c6
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6131
Reviewed-by: https://github.com/tcl3 ✅

Libraries/LibWeb/DOM/ShadowRoot.cpp

@@ -7,6 +7,7 @@
 #include <LibWeb/Bindings/ShadowRootPrototype.h>
 #include <LibWeb/DOM/AdoptedStyleSheets.h>
 #include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/DocumentOrShadowRoot.h>
 #include <LibWeb/DOM/Event.h>
 #include <LibWeb/DOM/ShadowRoot.h>
 #include <LibWeb/HTML/HTMLTemplateElement.h>
@@ -119,6 +120,11 @@ WebIDL::ExceptionOr<void> ShadowRoot::set_html_unsafe(StringView html)
     return {};
 }
 
+GC::Ptr<Element> ShadowRoot::active_element()
+{
+    return calculate_active_element(*this);
+}
+
 CSS::StyleSheetList& ShadowRoot::style_sheets()
 {
     if (!m_style_sheets)