Roll Dart SDK from c962a50422d3 to 3a72a508f5a0 (1 revision) (#23747)

DEPS

@@ -35,7 +35,7 @@ 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': 'c962a50422d3791319934f04bceb6b25b68e08b7',
+  'dart_revision': '3a72a508f5a0de3ea3283bfc9c645174f2d39857',
 
   # 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: bb098e0655b9aaa0f722f7bdc244461e
+Signature: 6f4e629b6bf07ec5d811a0fbaf8db162
 
 UNUSED LICENSES: