Roll src/third_party/dart 2bf325900586..d6fed1f62444 (1 commits) (#18334)

diff --git a/DEPS b/DEPS
index 632b9b0..728d1ec 100644
--- a/DEPS
+++ b/DEPS
@@ -34,7 +34,7 @@
   # 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': '2bf325900586b041dbe94bd150d6a0bf90640c38',
+  'dart_revision': 'd6fed1f62444caf2c4a9decc975ec64e84c44865',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py