mrobinson changed the title layout: Consistenly use Stylo's more complete get_used_transform_style layout: Make the implementation of used TransformStyle more complete

Stylo was using a very incomplete method for calculating the used
`TransformStyle` for boxes, which didn't incorporate all of the grouping
properties from the specification. This change moves the functionality
into Servo (as cannot properly compute this value without
`FragmentFlags`) and makes it more complete. We still do not process the
value of `contain`, `mask-iamge`, and `mask-boarder-source` as we do not
support those values yet.
Incidentally, this also fixes a panic that we were causing in WebRender,
probably by going down a path that Gecko does not exercise.
Stylo PR: servo/stylo#388
Signed-off-by: Martin Robinson <martin@abandonedwig.info>

lukewarlow pushed a commit to lukewarlow/stylo that referenced this pull request

…servo#388)
It's not possible to properly calculate these only looking at style,
because the results depends on the used `overflow` value.
Servo PR: servo/servo#45629
Signed-off-by: Martin Robinson <martin@abandonedwig.info>

Loirooriol pushed a commit to servo/stylo that referenced this pull request

…#388)
It's not possible to properly calculate these only looking at style,
because the results depends on the used `overflow` value.
Servo PR: servo/servo#45629
Signed-off-by: Martin Robinson <martin@abandonedwig.info>