Roll src/third_party/skia 640898f:1864bfa
Roll src/third_party/skia 640898f:1864bfa

Summary of changes available at:
https://chromium.googlesource.com/skia/+log/640898f..1864bfa

CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
TBR=reed@google.com

Commits in this roll:
1864bfa caryclark@google.com add radial gradient hard stop test
6b38eab reed@google.com add helper to create RSXform w/ anchorPt
6c72d57 yang.zhang@linaro.org Optimize RGB16 blitH functions with NEON for ARM platform.

Review URL: https://codereview.chromium.org/1260163007

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#341116}

Chilledheart/chromium,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,Just-D/chromium-1,Just-D/chromium-1,Just-D/chromium-1,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,axinging/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,Just-D/chromium-1