LibWeb/HTML: Stub TextTrack IDL interface

Author: https://github.com/jamierocks
Commit: 67e3ac8916
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/333
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/HTML/HTMLTrackElement.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,6 +8,7 @@
 #pragma once
 
 #include <LibWeb/HTML/HTMLElement.h>
+#include <LibWeb/HTML/TextTrack.h>
 
 namespace Web::HTML {
 
@@ -17,10 +19,17 @@ class HTMLTrackElement final : public HTMLElement {
 public:
     virtual ~HTMLTrackElement() override;
 
+    JS::Handle<TextTrack> track() { return m_track; }
+
 private:
     HTMLTrackElement(DOM::Document&, DOM::QualifiedName);
 
     virtual void initialize(JS::Realm&) override;
+
+    // ^DOM::Element
+    virtual void attribute_changed(FlyString const& name, Optional<String> const& value) override;
+
+    JS::GCPtr<TextTrack> m_track;
 };
 
 }