Roll external/skia da066b865..4d41b8f2f (2 commits)

https://skia.googlesource.com/skia.git/+log/da066b865..4d41b8f2f

2017-07-13 fmalita@chromium.org Remove dead gradient perspective code
2017-07-13 bsalomon@google.com Make MSAAPathOp a non-legacy GrMeshDrawOp

Test: Presubmit checks will test this change.
Change-Id: I086441d4a3f7250ee60c74a5051b7347753835b5