Consider the following case:
<image style="list-style-image: url(foo.png)"></image>
image.style.MozAppearance = "something"
The early return was preventing us from clearing the image.
This is an ancient bug, but it has started happening in the browser chrome
because the lack of lazy frame construction for XUL elements makes us construct
elements with an outdated style, which means in this case that they wouldn't
have the -moz-appearance rule applied yet.
Differential Revision: https://phabricator.services.mozilla.com/D52112
--HG--
extra : moz-landing-system : lando
8911c60203