Roll Dart SDK from 0507607 to 2a693f4 (1 revision)

https://dart.googlesource.com/sdk.git/+log/0507607e1380..2a693f47e303

2021-08-25 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.15.0-53.0.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 cbracken@google.com,dart-vm-team@google.com 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': '0507607e13808426fb90fd0b4a5e751a3fe7e029',
+  'dart_revision': '2a693f47e30369f1b27dd23d7fbf4eb39db0f244',
 
   # 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: e1c995f2932d929d29c9b532125f8196
+Signature: 54eba78976568ea4ee4b74f0c5bb3ec3
 
 UNUSED LICENSES: