Roll src/third_party/skia ac6d4c0c8eae..346e10e8ae1a (3 commits) (#7959)

https://skia.googlesource.com/skia.git/%2Blog/ac6d4c0c8eae..346e10e8ae1a

git log ac6d4c0c8eae8a90185da16ab01c81921669cc1f..346e10e8ae1afc705dd61c0ec006e652cee22ee5 --date=short --no-merges --format=%ad %ae %s
2019-02-26 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 377d493a0847..9a16248dedf3 (2 commits)
2019-02-26 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 53c8957c337d..377d493a0847 (1 commits)
2019-02-26 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset

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': 'ac6d4c0c8eae8a90185da16ab01c81921669cc1f',
+  'skia_revision': '346e10e8ae1afc705dd61c0ec006e652cee22ee5',
 
   # 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: edaf760039f49bc2a4eec3c5617d3293
+Signature: 46df429804e74ade28aec05fd44a2c05
 
 UNUSED LICENSES: