split out SkDraw_text functions

Bug: skia:
Change-Id: I1cbce64fe137011e664133a1ec51feaa87898529
Reviewed-on: https://skia-review.googlesource.com/c/160023
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed