Use SkTextEncoding enum instead of macros.

Change-Id: I4b6259590fa0693ee0522b4999a1c0fe250b173d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212504
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
111 files changed