The TSAN bots fail regularly with races on fConvexity. Very annoying.
We used to have this very same problem with SkPath::fFirstDirection
until we made it atomic. This does the same to fConvexity.
This makes the field as lightly atomic as possible, with all operations
using a relaxed memory order. The value of fConvexity isn't guarding
any other non-atomic memory or implying any other writes have happened
so I don't think we need anything beyond relaxed here.
Change-Id: I0da1f892dc2b7072d692ce8b460fb1862aebef77
Reviewed-on: https://skia-review.googlesource.com/52180
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
b9b5de5c66