Roll external/skia ba8ca0a12..2629ea36d (2 commits)

https://skia.googlesource.com/skia.git/+log/ba8ca0a12..2629ea36d

2017-05-08 iannucci@google.com Manually roll recipes.
2017-05-08 robertphillips@google.com Re-enable deferred proxies in Chrome

Test: Presubmit checks will test this change.
Change-Id: I26a9a161ab69266605726099c9fdab45c3c834d1