replace SkFont::glyphsToUnichars with SkFontPriv::GlyphsToUnichars

Change-Id: Ideea45d7b23eb9e821664be96d480a7d64c69a42
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/215826
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
3 files changed