Make SkAtlasTextTarget use glyph IDs

Bug: skia:
Change-Id: Idefd69f02f62fea22c41a3476676773221c3ae81
Reviewed-on: https://skia-review.googlesource.com/73700
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
4 files changed