Roll src/third_party/dart 96cf889e6b7b..5b21a43c556c (18 commits) (#17202)

DEPS

@@ -34,7 +34,7 @@ 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': '96cf889e6b7bd9e596cbd08849c5351a38eec097',
+  'dart_revision': '5b21a43c556c55ee788aee4fdbd8563a7fe329ab',
 
   # 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: b46604502b5e8b62409e2784397b1b16
+Signature: fe06cabd4e8412d069b983c21f83eeaf
 
 UNUSED LICENSES: