Roll Dart SDK from fcaedc6d9587 to 2cec6af2652f (1 revision) (#21257)

diff --git a/DEPS b/DEPS
index dae7ca3..1a7ce78 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': 'fcaedc6d9587c005161a90d64bd32fd858760d55',
+  'dart_revision': '2cec6af2652ff859979987f568d18193df48163e',
 
   # 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 526a5df..6de43bc 100644
--- a/ci/licenses_golden/licenses_third_party
+++ b/ci/licenses_golden/licenses_third_party
@@ -1,4 +1,4 @@
-Signature: 962e5633685d33a69b598d96ab4c063c
+Signature: 3efa8608e94837e1d3aef3cd39f58189
 
 UNUSED LICENSES: