Roll src/third_party/skia d978b90d205d..50e24d7d5f52 (4 commits) (#7743)

https://skia.googlesource.com/skia.git/%2Blog/d978b90d205d..50e24d7d5f52

git log d978b90d205d76206e9d15cd8c4db8743350e023..50e24d7d5f52724b4286078a813eb253e710fe47 --date=short --no-merges --format=%ad %ae %s
2019-02-07 csmartdalton@google.com Add a mechanism for GMs to silently exclude themselves from Gold
2019-02-07 benjaminwagner@google.com [infra] Update Win10 in Skolo.
2019-02-07 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2019-02-07 csmartdalton@google.com Reland "Add a GpuGM class for GPU-only tests"

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 (fmalita@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': 'd978b90d205d76206e9d15cd8c4db8743350e023',
+  'skia_revision': '50e24d7d5f52724b4286078a813eb253e710fe47',
 
   # 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: ac5c698899bb2b83190448b35b3c66d7
+Signature: 245c8f04811974866afdeaff80f56139
 
 UNUSED LICENSES: