Creating an hb_face can be quite expensive, cache them.
This implementation is similar to the super simple caching strategy used
by libtxt. It uses a simple global LRU cache from SkFontID to hb_hbface
of size 100.
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/289442
Change-Id: I971620f7aaaf2d7b6902da8681e29d6d458429ed
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/290761
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
4651b99f32