[Cocoa] Migrate off SPI in Font::platformWidthForGlyph()
Created attachment 406889 [details] Patch
<rdar://problem/51631817>
<rdar://problem/67451718>
*** Bug 215674 has been marked as a duplicate of this bug. ***
Committed r266666: <https://trac.webkit.org/changeset/266666> All reviewed patches have been landed. Closing bug and clearing flags on attachment 406889 [details].