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>
Also implements :link, :visited, and :any-link more efficiently, and stops
matching :-moz-read-only in everything that is not read-write, which is kind of
dumb, and probably creates some artifacts.
MozReview-Commit-ID: 6BQqi7nAWdT
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
The primary idea of this patch is to ditch the rigid enum of Previous/Current
styles, and replace it with a series of indicators for the various types of
work that needs to be performed (expanding snapshots, rematching, recascading,
and damage processing). This loses us a little bit of sanity checking (since
the up-to-date-ness of our style is no longer baked into the type system), but
gives us a lot more flexibility that we'll need going forward (especially when
we separate matching from cascading). We also eliminate get_styling_mode in
favor of a method on the traversal.
This patch does a few other things as ridealongs:
* Temporarily eliminates the handling for transfering ownership of styles to the
frame. We'll need this again at some point, but for now it's causing too much
complexity for a half-implemented feature.
* Ditches TRestyleDamage, which is no longer necessary post-crate-merge, and is
a constant source of compilation failures from either needing to be imported
or being unnecessarily imported (which varies between gecko and servo).
* Expands Snapshots for the traversal root, which was missing before.
* Fixes up the skip_root stuff to avoid visiting the skipped root.
* Unifies parallel traversal and avoids spawning for a single work item.
* Adds an explicit pre_traverse step do any pre-processing and determine whether
we need to traverse at all.
MozReview-Commit-ID: IKhLAkAigXE
