Roll Dart SDK from 051994cd182f to 0050849aff4e (1 revision) (#28178)

DEPS

@@ -39,7 +39,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '051994cd182ffaa465edb2ea1b9264bff814bd0c',
+  'dart_revision': '0050849aff4ef07d436260024c9ec0b9fa728e0e',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

-Signature: 144158d70e0b7d3349c889725f01e81f
+Signature: 1dce0700d7db3932615700c159c2ec76
 
 UNUSED LICENSES: