Split getOrCreateCache into a SkFont and descriptor based calles

Change-Id: Ie4724137baf3d355b94bd9966cc381a688c465fb
Reviewed-on: https://skia-review.googlesource.com/c/190671
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed