Behavior-wise this only removes the HasAttr(src) check, and adds the IsEmpty()
check to the alt attribute value, since this function is only called for <img>
and <input>.
But it also cleans up a bit.
Differential Revision: https://phabricator.services.mozilla.com/D11194
--HG--
extra : source : 803b224d52a0940b4fb4b3b9cffc6a1fa6e5d4ee
