Currently ANGLE-WebGL can't be built with the WPE port and requires some minor code changes both to build and to work.
Created attachment 448840 [details] Patch
Note that there are important steps to take when updating ANGLE. See https://trac.webkit.org/wiki/UpdatingANGLE
Created attachment 448844 [details] Patch
Committed r287920 (245953@main): <https://commits.webkit.org/245953@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 448844 [details].
<rdar://problem/87451165>