Roll Dart SDK from 238108dd9c6f to d6fa0d686082 (1 revision) (#28461)

diff --git a/DEPS b/DEPS
index 8845612..da281bd 100644
--- a/DEPS
+++ b/DEPS
@@ -39,7 +39,7 @@
   # 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': '238108dd9c6fbb457258599e3164536e9e446a7a',
+  'dart_revision': 'd6fa0d686082ec9f2957bce7e2de30b222fee082',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
diff --git a/ci/licenses_golden/licenses_third_party b/ci/licenses_golden/licenses_third_party
index c665306..cdb2a43 100644
--- a/ci/licenses_golden/licenses_third_party
+++ b/ci/licenses_golden/licenses_third_party
@@ -1,4 +1,4 @@
-Signature: 4b86c1b92b3f482dbfb90bee2cb27719
+Signature: 902cd27abf70686b2fe8cfe5ab8d655d
 
 UNUSED LICENSES: