Roll Dart SDK from 35c81c5 to 4c4bf41 (1 revision)

https://dart.googlesource.com/sdk.git/+log/35c81c55d91f..4c4bf41da092

2021-08-24 [email protected] Version 2.15.0-51.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC [email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter Engine: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -39,7 +39,7 @@ 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': '35c81c55d91fead7af6fa4e8e9b73959f62e9dfe',
+  'dart_revision': '4c4bf41da09210cd8fb404006a97b2103923d48f',
 
   # 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

@@ -1,4 +1,4 @@
-Signature: 91ef020f7cbab02735feb1e204f5c858
+Signature: db68378fca15712b4a02dc80c68c9bf9
 
 UNUSED LICENSES: