- Include vertical border spacing in row group offset calculation so
that they are axis-aligned with child row/cell elements. This makes it
so there isn't horizontal and vertical overflow caused by child
row/cell elements.
- Include horizontal border spacing in tr width calculations. This makes
it so tr elements don't have overflow anymore when there are multiple
columns.
- Apply vertical caption offset to row group top offset.
- Don't double-count top padding when calculating vertical offset for
tr and row groups.
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.
On style update, we have to preserve the invariant established when we
built the layout tree - some properties are applied to the table wrapper
and the table box values are reset to their initial values.
This also ensures that the containing block of a table box is always a
table wrapper, which isn't the case if we set absolute position on the
box instead of the wrapper.
Fixes#19452.
