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>
It turns out that it's problematic to embed ThreadLocalStyleContext within
LayoutContext, because parameterizing the former on TElement (which we do
in the next patch) infects all the traversal stuff with the trait parameters,
which we don't really want.
In general, it probably makes sense to use separate scoped TLS types for
the separate DOM and Flow tree passes, so we can add a different ScopedTLS
type for the Flow pass if we ever need it.
We also reorder the |scope| and |shared| parameters in parallel.rs, because
it aligns more with the order in style/parallel.rs. I did this when I was
adding a TLS parameter to all these functions, which I realized we don't need
for now.
