This code was written from scratch for Sky by copying what
linux did, however that doesn't match with the expectations
of the surrounding code. Instead here I just copied what Blink
was doing around this time by looking at:
https://blink.lc/blink/tree/Source/platform/fonts/mac/FontPlatformDataMac.mm?id=f0ab9794a9d1240ce5a57e510fdb82dbc8337906
Blink has since diverged from this codepath, but this at least
makes our FontPlatformData match how the rest of the mac code
expects it to operate. This is all way more complicated than
we need.
@chinmaygarde