Roll src/third_party/skia/ 3ab14ca95..6af677ff8 (1 commit).

https://chromium.googlesource.com/skia.git/+log/3ab14ca950d9..6af677ff8f54

$ git log 3ab14ca95..6af677ff8 --date=short --no-merges --format='%ad %ae %s'
2016-07-10 dvonbeck Changed SkLightingShader API to take in a shader as color source

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
TBR=msarett@google.com

Review-Url: https://codereview.chromium.org/2141473002
Cr-Commit-Position: refs/heads/master@{#404597}

DEPS

@@ -36,7 +36,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': '3ab14ca950d98a5c4d4c4a5f96ea8b0c984e0116',
+  'skia_revision': '6af677ff8f549751352847ceefda4538236c8a20',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.