Implemented by reusing AddMask display list item that was initially
added for `background-clip` property.
Progress on flashlight effect on https://null.com/games/athena-crisis
This change fixes handling for substep ii of the “F. Name From Content”
step at https://w3c.github.io/accname/#step2F in the “Accessible Name
and Description Computation” spec — to correctly include any ::before
and ::after pseudo-element content in the computation of accessible
names. Otherwise, without this change, accessible names unexpectedly
don’t include that pseudo-element content.
Layout nodes now only carry CSS computer values with them. The main
idea here is to give them only what they need to perform layout, and
leave the rest back in the DOM.
Put all the inherited members in one struct and all the non-inherited
ones in another.
This makes it clear which is which, and also makes it easy to copy all
the inherited values while ignoring the non-inherited ones.
