Skia roll 4473be8:6b0d6b4

https://skia.googlesource.com/skia/+log/4473be874f70d4a8833180a7aebcc9d8a0b1de9e..6b0d6b43cf662735dc804d8142383452c7f246f9

CQ_EXTRA_TRYBOTS=tryserver.blink:linux_blink_rel
TBR=djsollen@google.com

Review URL: https://codereview.chromium.org/509053002

Cr-Commit-Position: refs/heads/master@{#292192}

DEPS

@@ -38,7 +38,7 @@ vars = {
   # to update other nacl_*_revision's.
   'libvpx_revision': '563c46bb2d0e5d5c8b7d2c6c0c50f0283e9087de', # r291625
   'sfntly_revision': '1bdaae8fc788a5ac8936d68bf24f37d977a13dac',
-  'skia_revision': '4473be874f70d4a8833180a7aebcc9d8a0b1de9e',
+  'skia_revision': '6b0d6b43cf662735dc804d8142383452c7f246f9',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.