Reland "Simplify SkTypeface::charsToGlyphs API to require UTF32 input"

This is a reland of fde841de44a63701b0a4396da35893f348559ce9

Original change's description:
> Simplify SkTypeface::charsToGlyphs API to require UTF32 input
> 
> Change-Id: I486713c496c40103eef13fa6068ac4d69e32f606
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/207865
> Commit-Queue: Ben Wagner <bungeman@google.com>
> Reviewed-by: Ben Wagner <bungeman@google.com>

Change-Id: I5162c93b3ea6146d09334545744b791d993397b8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208679
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
27 files changed