Roll src/third_party/skia 81e8d3b..4a152d3 (2 commits) (#13281)

https://skia.googlesource.com/skia.git/+log/81e8d3b29662..4a152d340f06

git log 81e8d3b..4a152d3 --date=short --no-merges --format='%ad %ae %s'
2019-10-22 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update Go deps
2019-10-22 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 26c6c4a..23f9c25 (2 commits)

Created with:
  gclient setdep -r src/third_party/skia@4a152d340f06

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 michaelludwig@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=michaelludwig@google.com

Author: skia-flutter-autoroll

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': '81e8d3b296629532589e58625eec2a59378edf35',
+  'skia_revision': '4a152d340f06e5907c04d8362e39e539f06d509b',
 
   # 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

@@ -1,4 +1,4 @@
-Signature: 1de4c64848adec6c9e7d9357434573e8
+Signature: f8604527c0e87f541d803dd42493652d
 
 UNUSED LICENSES: