Roll src/third_party/skia 4dbb96d..f6faf2f (7 commits) (#7977)

https://skia.googlesource.com/skia.git/%2Blog/4dbb96dfaa04..f6faf2fcea7b

git log 4dbb96d..f6faf2f --date=short --no-merges --format=%ad %ae %s
2019-02-27 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 9f20dd7..009696c (2 commits)
2019-02-27 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 1bc7ee9..6c9fb0e (1 commits)
2019-02-27 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 7f6f891..1bc7ee9 (1 commits)
2019-02-26 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 54c4772..7f6f891 (1 commits)
2019-02-26 csmartdalton@google.com Reland "Stack-allocate pipelines for GrMeshDrawOp"
2019-02-19 mtklein@google.com remove mention of SkPaintDefaults_Flags
2019-02-26 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 8adf1fc..54c4772 (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.

Author: skia-flutter-autoroll

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': '4dbb96dfaa04868b4ed00ca90513097b2d987625',
+  'skia_revision': 'f6faf2fcea7b8bcfae0e5be29f9c292da8703c97',
 
   # 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

@@ -1,4 +1,4 @@
-Signature: 724f50e9f5ec65dcf10c8d1cfcd729df
+Signature: ff3c3602efacd16b443f1da56d22115f
 
 UNUSED LICENSES: