This is in preparation of a cascade optimization for custom properties.
This fixes various fishiness around our StyleBuilder stuff. In particular,
StyleBuilder::for_derived_style (renamed to for_animation) is only used to
compute specified values, and thus doesn't need to know about rules, visited
style, or other things like that.
The flag propagation that was done in StyleAdjuster is now done in StyleBuilder,
since we know beforehand which ones are always inherited, and it simplified the
callers and the StyleAdjuster code. It also fixed some fishiness wrt which flags
were propagated to anon boxes and text.
The text-decoration-lines bit is interesting, because the way it was implemented
in #17722 meant that display: contents elements did get HAS_DECORATION_LINES
flags only if its parent also had it, so in practice the Contents check
preserves behavior, but it's only an optimization looking at Gecko's call-sites,
so we can remove it too.
MozReview-Commit-ID: 6BHCyEO2U8c
Unfortunately this means that we lose the NS_STYLE_INHERIT_BIT optimization to
avoid posting changes if we had not requested the struct. In practice, I'm not
sure this optimization matters much, though, and we already compare all the
structs anyway.
We _could_ keep a weak parent pointer from the text style if needed, given we're
going to keep alive the text style at least until the parent style context goes
away, so should be safe, but I don't think the extra churn is worth it, to be
honest. Happy to do so as part of bug 1368290 if you think it's worth it.
Bug: 1385896
Reviewed-by: heycam
MozReview-Commit-ID: ka6tNwf4Ke
This will allow us to fix propagation of text-decoration, and also to implement
inlinization of ruby kids.
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
