Roll src/third_party/skia 4273a150f84d..ba91f65f2070 (6 commits) (#8225)

https://skia.googlesource.com/skia.git/%2Blog/4273a150f84d..ba91f65f2070

git log 4273a150f84d70a9acc340261fd5e7be1af310a5..ba91f65f20701ce6ae6b43556d1ffb7c8be61a73 --date=short --no-merges --format=%ad %ae %s
2019-03-19 jvanverth@google.com Tweaks to Metal pipeline state.
2019-03-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 3e485a4f3ec8..5851ef46d285 (1 commits)
2019-03-20 kjlubick@google.com Make ios actually fail
2019-03-20 brianosman@google.com Remove all of the _as_paths GMs
2019-03-19 kjlubick@google.com [canvaskit] Add requestAnimationFrame to SkSurface
2019-03-20 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).

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 (brianosman@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': '4273a150f84d70a9acc340261fd5e7be1af310a5',
+  'skia_revision': 'ba91f65f20701ce6ae6b43556d1ffb7c8be61a73',
 
   # 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: 0a2fd38c998e20b99ec89e55e3387451
+Signature: affcc1ae5b1bd60f3e3e4839e61b054a
 
 UNUSED LICENSES:
 
@@ -4228,7 +4228,6 @@ FILE: ../../../third_party/skia/gm/pictureshadercache.cpp
 FILE: ../../../third_party/skia/gm/radial_gradient_precision.cpp
 FILE: ../../../third_party/skia/gm/savelayer.cpp
 FILE: ../../../third_party/skia/gm/shadowutils.cpp
-FILE: ../../../third_party/skia/gm/shapes_as_paths.cpp
 FILE: ../../../third_party/skia/gm/simple_magnification.cpp
 FILE: ../../../third_party/skia/gm/srgb.cpp
 FILE: ../../../third_party/skia/gm/testgradient.cpp