In legacy layout, anonymous text wrappers were inheriting the `overflow`
and `text-overflow` properties. This results in the creation of extra
clipping for these anonymous wrappers which could clip away floats. We
will likely implement `text-overflow` differently in non-legacy layout.
This change marks all legacy layout pseudo elements as "legacy" and also
adds a new pseudo element for non-legacy layout that does not inherit
`overflow`.
Fixes#30562.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Refactor the scrolling and scrollable area calculation on the window
object, to make it better match the specification. This has some mild
changes to behavior, but in general things work the same as they did
before. This is mainly preparation for properly handling viewport
propagation of the `overflow` property but seems to fix a few issues as
well.
There is one new failure in Layout 2020 regarding `position: sticky`,
but this isn't a big deal because there is no support for `position:
sticky` in Layout 2020 yet.
Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
