Roll src/third_party/skia 1b466f7:afbf2d6

Summary of changes available at:
https://chromium.googlesource.com/skia/+log/1b466f7..afbf2d6

CQ_EXTRA_TRYBOTS=tryserver.blink:linux_blink_rel,linux_blink_dbg
TBR=robertphillips@google.com

Review URL: https://codereview.chromium.org/617763004

Cr-Commit-Position: refs/heads/master@{#297520}

DEPS

@@ -35,7 +35,7 @@ vars = {
   'boringssl_git': 'https://boringssl.googlesource.com',
   'libvpx_revision': 'efe9712d52c2d216fb3d1ceb508b8148847a7e4b',
   'sfntly_revision': '1bdaae8fc788a5ac8936d68bf24f37d977a13dac',
-  'skia_revision': '1b466f7e21004257afeb35cd008768e3b541dca9',
+  'skia_revision': 'afbf2d6273cd22c683f20a7e5773843876af3085',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.