Roll src/third_party/skia b1ade2a4261e..a268dfb74add (5 commits) (flutter/engine#11643)

https://skia.googlesource.com/skia.git/+log/b1ade2a4261e..a268dfb74add

git log b1ade2a4261e..a268dfb74add --date=short --no-merges --format='%ad %ae %s'
2019-08-28 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-08-28 bungeman@google.com Add test for baseline snapping.
2019-08-28 dragonbear@google.com Override operator delete for GrCpuBuffer
2019-08-28 halcanary@google.com SkPlainTextEditor/app: cycle typeface with ctrl-0
2019-08-28 halcanary@google.com SkQP: Use SK_GL macro

Created with:
  gclient setdep -r src/third_party/skia@a268dfb74add

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 stani@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=stani@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': 'b1ade2a4261ea7fc372a5f9ad2481bf9d57ac59a',
+  'skia_revision': 'a268dfb74add0aeb299800b4b2d88ed9c8c1ca4c',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

engine/src/flutter/ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: 298d611ba9d5a21424c37d0f171745e5
+Signature: 0562bd9b68450b2a9eb8492d377f11f8
 
 UNUSED LICENSES: