This adds a way for users to query the axis parameters for a typeface.
Change-Id: Idc2ac0d84bc7ae2ca484ae410cba5b01883418e5
Reviewed-on: https://skia-review.googlesource.com/137706
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
