This is still not completely perfect in that in principle it is possible for add-ons to add toolbars that they force to be non-transparent, but there is no way to select for that. Keeping a list of toolbars we know are transparent would break the more common case of third-party toolbars that do behave 'normally' when used with lightweight themes. So for now, just assume navigator-toolbox is all transparent when a lwtheme is in use.
MozReview-Commit-ID: 4I8l3Bn7DQf
bfd033aef5
