Roll external/skia 76fcb10f4..8d1e0ac99 (9 commits)
https://skia.googlesource.com/skia.git/+log/76fcb10f4..8d1e0ac99
2017-05-05 jvanverth@google.com More analytic shadow refactoring.
2017-05-05 msarett@google.com Stub encoding impls for clients without libraries
2017-05-05 msarett@google.com Fix implicit ptr to bool
2017-05-05 reed@google.com composecolorfilter can now append stages
2017-05-05 benjaminwagner@google.com Add bigrect GM.
2017-05-05 mtklein@chromium.org add a new hsl GM
2017-05-05 halcanary@google.com SkTypeface: remove old virtual onGetAdvancedMetrics, since https://crrev.com/2860293003
2017-05-05 reed@google.com tweak the gaussian quartic
2017-05-05 msarett@google.com SkEncoder: Rename files, change webp API, for consistency
Test: Presubmit checks will test this change.
Change-Id: I2bdc4c78c1e210a1bb70116d3094e82adaf4021d