LibWeb: Implement creation of fresh top-level traversables

Co-authored-by: Andreas Kling <kling@serenityos.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.cpp b/Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.cpp
index c8f81ff651..754f3f3ad0 100644
--- a/Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.cpp
+++ b/Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.cpp
@@ -35,6 +35,23 @@ void BrowsingContextGroup::visit_edges(Cell::Visitor& visitor)
         visitor.visit(context);
 }
 
+// https://html.spec.whatwg.org/multipage/document-sequences.html#creating-a-new-browsing-context-group-and-document
+auto BrowsingContextGroup::create_a_new_browsing_context_group_and_document(Page& page) -> WebIDL::ExceptionOr<BrowsingContextGroupAndDocument>
+{
+    // 1. Let group be a new browsing context group.
+    // 2. Append group to the user agent's browsing context group set.
+    auto group = Bindings::main_thread_vm().heap().allocate_without_realm<BrowsingContextGroup>(page);
+
+    // 3. Let browsingContext and document be the result of creating a new browsing context and document with null, null, and group.
+    auto [browsing_context, document] = TRY(BrowsingContext::create_a_new_browsing_context_and_document(page, nullptr, nullptr, group));
+
+    // 4. Append browsingContext to group.
+    group->append(browsing_context);
+
+    // 5. Return group and document.
+    return BrowsingContextGroupAndDocument { group, document };
+}
+
 // https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-browsing-context-group
 JS::NonnullGCPtr<BrowsingContextGroup> BrowsingContextGroup::create_a_new_browsing_context_group(Web::Page& page)
 {