[canvaskit] Add getGlyphIDs to Typeface API

Bug: skia:12113
Change-Id: Ice0986370a76b7051de50deb6c6ace644eb4e6f4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/422016
Reviewed-by: Ben Wagner <bungeman@google.com>
7 files changed