Roll src/third_party/skia/ 3a9305383..8d64ee779 (1 commit)

https://skia.googlesource.com/skia.git/+log/3a9305383169..8d64ee779599

$ git log 3a9305383..8d64ee779 --date=short --no-merges --format='%ad %ae %s'
2017-10-04 bungeman Update SkBufferHead fRefCnt to std::atomic.

Created with:
  roll-dep src/third_party/skia


Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel
TBR=scroggo@chromium.org

Change-Id: I053b4db1cabb725cbb6ae07441270e7c53ec1d96
Reviewed-on: https://chromium-review.googlesource.com/701672Reviewed-by: Skia Deps Roller <skia-deps-roller@chromium.org>
Commit-Queue: Skia Deps Roller <skia-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506766}

DEPS

@@ -45,7 +45,7 @@ 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': '3a9305383169524488cb84e9bd5dba95520c3ca7',
+  'skia_revision': '8d64ee7795991ceaa2346a63bd9660e4722f346e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.