impl SkFont::measureText

Bug: skia:
Change-Id: Ibd76b72e8486d89acf4ce9babc18f35357884b2d
Reviewed-on: https://skia-review.googlesource.com/c/170276
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed