Ideally this would be lazy, but eventually we're going to need to restyle in
RebuildAllStyleData anyway, which would require us to have the style up to date,
so no need to complicate our lives.
MozReview-Commit-ID: AlmUGRCNm2z
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
The setup is quite different to Servo-land, so add a comment about the different
setup.
Also, check viewport rules when flushing stylesheets. I believe that the
previous behavior is plain wrong, though I haven't taken the time to come up
with a test case.
In any case, it doesn't hurt any of both back-ends.
MozReview-Commit-ID: 46gtTkesOsr
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>