Roll src/third_party/skia 6abaff3041a3..559ffe4a23ce (2 commits) (#12444)

https://skia.googlesource.com/skia.git/+log/6abaff3041a3..559ffe4a23ce

git log 6abaff3041a3..559ffe4a23ce --date=short --no-merges --format='%ad %ae %s'
2019-09-25 brianosman@google.com Particles: Added particle flags for tracking state (one-time triggers, etc)
2019-09-25 mtklein@google.com poor man's contention profiler

Created with:
  gclient setdep -r src/third_party/skia@559ffe4a23ce

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC bungeman@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

Bug: None
TBR=bungeman@google.com

DEPS

@@ -26,7 +26,7 @@ vars = {
   'skia_git': 'https://skia.googlesource.com',
   # OCMock is for testing only so there is no google clone
   'ocmock_git': 'https://github.com/erikdoe/ocmock.git',
-  'skia_revision': '6abaff3041a3eb140b82d091ef2aa35063b5c69c',
+  'skia_revision': '559ffe4a23cea3279642dcac7335164348d8e344',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

ci/licenses_golden/licenses_skia

-Signature: 7394b706e31be8fb341b323f8527d34e
+Signature: adb6f9c0d3af94ec21b2ca06e48d0edf
 
 UNUSED LICENSES: