Roll external/skia 1478f74aa..035671491 (3 commits)

https://skia.googlesource.com/skia.git/+log/1478f74aa..035671491

2017-05-04 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2017-05-04 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2017-05-03 msarett@google.com Add SkImage::makeColorSpace() with correct transfer fn behavior

Test: Presubmit checks will test this change.
Change-Id: I4d18a82545acb6e0a83706f812a818df7e8c9037