simplify path validate

Reduce path validation interfaces,
deferring the harder work of rewriting
the callers until later.

R=reed@google.com,enne@chromium.org

Change-Id: Iea56f1cd1be93bb1d96b50836a9bd3cd4872ad23
Reviewed-on: https://skia-review.googlesource.com/37541
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Adrienne Walker <enne@chromium.org>
3 files changed