Roll src/third_party/skia 213aa46af167..176b214f91bc (2 commits) (flutter/engine#9100)

https://skia.googlesource.com/skia.git
/%2Blog/213aa46af167..176b214f91bc

git log 213aa46af167261b39803290294a53a77cbbd21d..176b214f91bc1ce302621f5796bfd7a72d5b3f5d --date=short --no-merges --format=%ad %ae %s
2019-05-28 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-05-24 bsalomon@google.com Define SK_GL in Flutter.

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 (kjlubick@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': '213aa46af167261b39803290294a53a77cbbd21d',
+  'skia_revision': '176b214f91bc1ce302621f5796bfd7a72d5b3f5d',
 
   # 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: 3b4897f30339ac11e9af0e823aa1f858
+Signature: 1401d4a0d1ee0eed40328f985581b6c1
 
 UNUSED LICENSES: