This Widget (base QLabel) is designed to show the cover art. It handles right-click, and show a context menu that has only one entry:

- Download cover art

When the user clicks it, vlc downloads the cover art (or finds it in the cache), and displays it when downloaded
(cherry picked from commit 4dd472bb)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>