LibWeb: Implement BarProp properties for Window

Author: https://github.com/Totto16
Commit: b66e7ac1ba
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3810
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/tcl3 ✅

Libraries/LibWeb/HTML/BarProp.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025, the Ladybird developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Realm.h>
+#include <LibWeb/Bindings/BarPropPrototype.h>
+#include <LibWeb/HTML/BarProp.h>
+#include <LibWeb/HTML/Window.h>
+
+namespace Web::HTML {
+
+GC_DEFINE_ALLOCATOR(BarProp);
+
+GC::Ref<BarProp> BarProp::create(JS::Realm& realm)
+{
+    return realm.create<BarProp>(realm);
+}
+
+BarProp::BarProp(JS::Realm& realm)
+    : Bindings::PlatformObject(realm)
+{
+}
+
+// https://html.spec.whatwg.org/multipage/nav-history-apis.html#dom-barprop-visible
+bool BarProp::visible() const
+{
+    // 1. Let browsingContext be this's relevant global object's browsing context.
+    auto& global_object = HTML::relevant_global_object(*this);
+    auto* browsing_context = as<HTML::Window>(global_object).associated_document().browsing_context();
+
+    // 2. If browsingContext is null, then return true.
+    if (!browsing_context) {
+        return true;
+    }
+
+    // 3. Return the negation of browsingContext's top-level browsing context's is popup.
+    return browsing_context->top_level_browsing_context()->is_popup() != TokenizedFeature::Popup::Yes;
+}
+
+void BarProp::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(BarProp);
+}
+}