hide SkFont::containsText

Bug: skia:
Change-Id: I197addb0ea1da57083283b30e19e290cdaf8dac6
Reviewed-on: https://skia-review.googlesource.com/c/188581
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
4 files changed