I've chosen this approach mainly because there's no other good way to guarantee
the model is correct than holding the snapshots alive until a style refresh.
What I tried before this (storing them in a sort of "immutable element data") is
a pain, since we call into style from the frame constructor and other content
notifications, which makes keeping track of which snapshots should be cleared an
which shouldn't an insane task.
Ideally we'd have a single entry-point for style, but that's not the case right
now, and changing that requires pretty non-trivial changes to the frame
constructor.
MozReview-Commit-ID: FF1KWZv2iBM
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
Note that, while the comment is correct that there is a fair amount of -moz-any
usage in the UA sheet, it's always used as an ancestor selector, and thus ignored
for our purposes. Nevertheless, it's straightforward enough to support properly,
so we do that here.
MozReview-Commit-ID: Kz1yNfPUIaP
This improves cache locality and reduces allocations during parsing.
Note that this reverses the iteration order within a sequence of simple selectors,
but that shouldn't matter.
Also, simplify all the pre-snapshot attribute hacks in the script and style
code.
MozReview-Commit-ID: 6c9ipeb7Tnr
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
