Right now we do a lot of useless string copying. In order to avoid transcoding
to utf-16 during layout, make sure to use nsCString at a few related places.
I may revisit this since we're storing other line names as atoms in some places.
So it may be better to just use atoms everywhere.
But that'd be a different patch either way.
Depends on D35116
Differential Revision: https://phabricator.services.mozilla.com/D35117
--HG--
extra : moz-landing-system : lando