Roll external/skia 5addedd59..f7beee7cd (1 commits)

https://skia.googlesource.com/skia.git/+log/5addedd59..f7beee7cd

2017-05-26 fmalita@chromium.org Hide ctors of SkShader, SkImage & SkColorSpace

Test: Presubmit checks will test this change.
Change-Id: Ib2f8b781320d3eddcd9b8e700b5eeaca2d4db3ba