Roll src/third_party/skia bcfbf6e94c22..ac6d4c0c8eae (1 commits) (#7958)

https://skia.googlesource.com/skia.git/%2Blog/bcfbf6e94c22..ac6d4c0c8eae

git log bcfbf6e94c2272b0a030a8763e2abcfe4b55395c..ac6d4c0c8eae8a90185da16ab01c81921669cc1f --date=short --no-merges --format=%ad %ae %s
2019-02-26 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 9b433073ba38..53c8957c337d (1 commits)

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-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 (scroggo@google.com), and stop
the roller if necessary.

DEPS

@@ -23,7 +23,7 @@ vars = {
   'fuchsia_git': 'https://fuchsia.googlesource.com',
   'github_git': 'https://github.com',
   'skia_git': 'https://skia.googlesource.com',
-  'skia_revision': 'bcfbf6e94c2272b0a030a8763e2abcfe4b55395c',
+  'skia_revision': 'ac6d4c0c8eae8a90185da16ab01c81921669cc1f',
 
   # 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: 186c1643cc6eaf037a08e71cb906d1e6
+Signature: edaf760039f49bc2a4eec3c5617d3293
 
 UNUSED LICENSES: