Roll external/skia 4d41b8f2f..907783bb7 (10 commits)
https://skia.googlesource.com/skia.git/+log/4d41b8f2f..907783bb7
2017-07-13 reed@google.com don't test index8 -- no longer supported
2017-07-13 bsalomon@google.com Add abandoned context check to SkImage::MakeFromDeferredTextureImageData
2017-07-13 ethannicholas@google.com Re-land of "converted GrSimpleTextureEffect to sksl"
2017-07-13 scroggo@google.com Fix computeOutputColorSpace
2017-07-13 reed@google.com add guard for api change in google3
2017-07-13 reed@google.com Revert "add guard for recent api change"
2017-07-13 robertphillips@google.com Remove renderTargetContext swapping from GaussianBlur method (take 2)
2017-07-13 robertphillips@google.com Revert "Remove renderTargetContext swapping from GaussianBlur method"
2017-07-13 robertphillips@google.com Remove renderTargetContext swapping from GaussianBlur method
2017-07-13 reed@google.com Guard to remove kIndex_8_SkColorType
Test: Presubmit checks will test this change.
Change-Id: I5d3656c1889bad28acabe7f9c7a51839b80cc385