Roll src/third_party/dart bc53ecefae52..f6acefa078be (4 commits) (#17344)

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': 'bc53ecefae523208155cea798c13dd430bcc30e2',
+  'dart_revision': 'f6acefa078be0cf448f18697a025684fbf5d0ea0',
 
   # 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: ec9289c8fd6a8d089a9d6c507cdcfc31
+Signature: da1bde54103c07da0fd99fa9e639a77b
 
 UNUSED LICENSES: