Roll external/skia 783c43658..02ab8cc29 (2 commits)

https://skia.googlesource.com/skia.git/+log/783c43658..02ab8cc29

2017-05-04 mtklein@chromium.org Revert "Factor out common code from sweep and linear."
2017-05-04 amaury.leleyzour@arm.com CRC32 no longer restricted to ARM64

Test: Presubmit checks will test this change.
Change-Id: I1e104ff27b0d75477ebbdc4a3d41f79443f7c77f