Roll Dart SDK from 3a764b7ae4d9 to 9807b83d5945 (3 revisions) (#18523)

diff --git a/DEPS b/DEPS
index 7b20c2b..0b6c565 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': '3a764b7ae4d90d1fc261e868b4fc909822aa2d0a',
+  'dart_revision': '9807b83d5945737bee990535b692ecec19774f54',
 
   # 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 97617b7..1b22a90 100644
--- a/ci/licenses_golden/licenses_third_party
+++ b/ci/licenses_golden/licenses_third_party
@@ -1,4 +1,4 @@
-Signature: faf8ceb9bbf3aadf1ca9264e85f2d891
+Signature: 318a911481d75c340e3561593238d07c
 
 UNUSED LICENSES: