new batch of docs
Docs-Preview: https://skia.org/?cl=141244
Bug: skia:
Change-Id: I5a285778baaee2734495374adeb7359d524e47e3
Reviewed-on: https://skia-review.googlesource.com/141244
Reviewed-by: Cary Clark <caryclark@skia.org>
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
