mask-border CSS shorthand

[stubbornella]

Description

The mask-border CSS property sets how the edges of an element are masked. It is a shorthand for mask-border-outset, mask-border-repeat, mask-border-slice, mask-border-source, and mask-border-width.

Specification

https://developer.mozilla.org/en-US/docs/Web/CSS/mask-border

Additional Signals

No response

[gsnedders]

https://wpt.fyi/results/css/css-masking?label=master&label=experimental&aligned&q=mask-border doesn't match much; we probably need to split through variants the following to have mask-border tests specifically:

css/css-masking/inheritance.sub.html
css/css-masking/mask-shorthand-subproperties-reset.html
css/css-masking/parsing/mask-valid.sub.html

[nt1m]

https://github.com/search?q=repo%3Awebkit%2Fwebkit+mask-box-image&type=code&p=1

This is just a renamed version of -webkit-mask-box-image, those LayoutTests could just be ported over to WPT if rendering tests are needed.