This patch just adds the new root paintable and updates the tests
expectations. The next patch will move painting logic from the layout
viewport to the paint viewport.
Pseudo-elements like ::before and ::after were discarded when their
content property was an empty string (ignoring whitespace), because they
are anonymous containers with no lines.
Our previous way around it was to add an empty line box (see b062a0fb7c)
however it didn't actually work for cases described in the previous
commit.
This makes avatars and cover arts square on last.fm and "fixes" the test
css-pseudo-element-should-not-be-affected-by-presentational-hints.html.
Unfortunately, this also regresses on block-and-inline/clearfix.html,
but that hopefully will be handled in subsequent commit.
Using fixed-point saturated arithmetics for CSSPixels allows to avoid
accumulating floating-point errors.
This implementation is not complete yet: currently saturated
arithmetics implemented only for addition. But it is enough to not
regress any of layout tests we have :)
See https://github.com/SerenityOS/serenity/issues/18566
The resolved property sets are stored with the element in a
per-pseudo-element array (same as for pseudo element layout nodes).
Longer term, we should stop storing this with elements entirely and make
it temporary state in StyleComputer somehow, so we don't waste memory
keeping all the resolved properties around.
This makes various gradients show up on https://shopify.com/ :^)
