pass a font to GlyphRunBuilder

- avoid using legacy paint->font converter
- call out that drawText exists just for testing
- simplify drawText to assume UTF8

Bug: skia:
Change-Id: Ide14d8581d4744827d2282e7983cc5e19070b21e
Reviewed-on: https://skia-review.googlesource.com/c/180641
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Herb Derby <herb@google.com>
9 files changed