Roll src/third_party/skia effcba4:647211f

Summary of changes available at:
https://chromium.googlesource.com/skia/+log/effcba4..647211f

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

Review URL: https://codereview.chromium.org/1019243003

Cr-Commit-Position: refs/heads/master@{#321374}

DEPS

@@ -42,7 +42,7 @@ vars = {
   'boringssl_git': 'https://boringssl.googlesource.com',
   'libvpx_revision': 'f80cf581e6e56ec3b28b118aebf98499b6bc156d',
   'sfntly_revision': '1bdaae8fc788a5ac8936d68bf24f37d977a13dac',
-  'skia_revision': 'effcba4a4d1a6fdfdd5ec440e10e1424b768182d',
+  'skia_revision': '647211f1243f2dc925588e75038be49cad7b5431',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.