Roll external/skia b59a9da7e..060d98203 (10 commits)
https://skia.googlesource.com/skia.git/+log/b59a9da7e..060d98203
2017-05-04 jvanverth@google.com Combine the ambient and spot alphas into the base color for geometric shadows.
2017-05-04 mtklein@chromium.org move dither after the transfer function
2017-05-04 jvanverth@google.com Fix spot shadow inset.
2017-05-04 benjaminwagner@google.com Turn on verbose logging for Valgrind_PreAbandonGpuContext bot.
2017-05-04 benjaminwagner@google.com Remove Nexus5 experimental tryjob.
2017-05-04 robertphillips@google.com Add GrGpuTextureProxyRef
2017-05-04 msarett@google.com Reland "Add SkImage::makeColorSpace() with correct transfer fn behavior"
2017-05-04 ethannicholas@google.com Revert "Revert "Revert "eliminated GrGLSLExpr"""
2017-05-04 halcanary@google.com src/pdf: code cleanup
2017-05-04 msarett@google.com Finish removal of SkImageInfo from SkPixelRef
Test: Presubmit checks will test this change.
Change-Id: Iad98b1975a45549df4e7a4a440c6cec1c620fbf4