Roll src/third_party/skia/ 689d02d4b..cf81fa995 (8 commits)

https://skia.googlesource.com/skia.git/+log/689d02d4b480..cf81fa995f38

$ git log 689d02d4b..cf81fa995 --date=short --no-merges --format='%ad %ae %s'
2018-02-15 benjaminwagner Use goma ensure_stop.
2018-03-12 reed update include path for SkBlurMask.h
2018-03-06 caryclark make paint flatten unflatten private
2018-03-12 scroggo Update piex
2018-03-12 herb Fix overflow in blur for VERY wide bitmaps.
2018-03-09 caryclark pathmeasure fuzzer
2018-03-09 herb Remove DetachCache and AttachCache.
2018-03-12 kjlubick Small cleanups suggested by ClangTidy

Created with:
  roll-dep src/third_party/skia


The AutoRoll server is located here: https://autoroll.skia.org

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

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


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
TBR=stephana@chromium.org

Change-Id: I57dd28ba7867321e61e4120be0ffc5dcd84cb5e3
Reviewed-on: https://chromium-review.googlesource.com/959164
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#542547}

DEPS

@@ -79,7 +79,7 @@ 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': '689d02d4b480289aacaeb2da83b93d733cdfcb0f',
+  'skia_revision': 'cf81fa995f3806d1c35b555fb9420488b8a14517',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.