better mediakey shortcut support
What is the problem you are facing?
Play/pause work fine with mediakey but next/previous does nothing.
What are the possible drawbacks or issues with the requested changes?
Nothing I can think about.
Chrome (by default) and Firefox (once you enable media.hardwaremediakeys.enabled in about:config) support mediakey.
With mediakey you can play/pause/next/prev media playing in a browser tab, directly from your keyboard builtin shortcut or from your system notification (like in Gnome).