Roll src/third_party/skia f6faf2fcea7b..ab3f8674c9d2 (2 commits) (flutter/engine#7980)

https://skia.googlesource.com/skia.git/%2Blog/f6faf2fcea7b..ab3f8674c9d2

git log f6faf2fcea7b8bcfae0e5be29f9c292da8703c97..ab3f8674c9d2b28356eda74cbd35b3a8a7835752 --date=short --no-merges --format=%ad %ae %s
2019-02-27 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset
2019-02-27 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 6c9fb0e6353c..ead1a345a36c (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': 'f6faf2fcea7b8bcfae0e5be29f9c292da8703c97',
+  'skia_revision': 'ab3f8674c9d2b28356eda74cbd35b3a8a7835752',
 
   # 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: ff3c3602efacd16b443f1da56d22115f
+Signature: b3bf5a7ca4cf5663793c3fccb721c742
 
 UNUSED LICENSES: