Roll src/third_party/skia 5831e1113332..fb18639804e7 (2 commits)

https://skia.googlesource.com/skia.git/+log/5831e1113332..fb18639804e7


git log 5831e1113332..fb18639804e7 --date=short --no-merges --format='%ad %ae %s'
2018-09-11 jvanverth@google.com Set ambient stroke to full width of blur.
2018-09-11 jvanverth@google.com Fix some overflowing integers in SkPolyUtils


Created with:
  gclient setdep -r src/third_party/skia@fb18639804e7

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

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;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
TBR=caryclark@chromium.org

Change-Id: Ic8b46387c77c6ea01d0df93b9e629b8cce8d47aa
Reviewed-on: https://chromium-review.googlesource.com/1220229Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#590430}

DEPS

@@ -105,7 +105,7 @@ 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': '5831e1113332a94cf87bf60beef71743604767e2',
+  'skia_revision': 'fb18639804e76e2ccdc2062eeca8b53b3d37d1b9',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.