LibWeb: Begin implementing media resource seeking

Author: https://github.com/trflynn89
Commit: 5a98a5529f
Pull-request: https://github.com/SerenityOS/serenity/pull/18296
Reviewed-by: https://github.com/Zaggy1024 ✅

Userland/Libraries/LibWeb/HTML/HTMLVideoElement.h

@@ -46,6 +46,7 @@ private:
 
     virtual void on_playing() override;
     virtual void on_paused() override;
+    virtual void on_seek(double, MediaSeekMode) override;
 
     JS::GCPtr<HTML::VideoTrack> m_video_track;
     RefPtr<Gfx::Bitmap> m_current_frame;