Roll Dart SDK from 21f5de0ad596 to 7879aa93da71 (1 revision) (#38804)

https://dart.googlesource.com/sdk.git/+log/21f5de0ad596..7879aa93da71

2023-01-12 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com Version 3.0.0-115.0.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 aaclarke@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

@@ -48,7 +48,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/main/DEPS
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '21f5de0ad5966cbee9e9784f90b8e45b6f4c082c',
+  'dart_revision': '7879aa93da71594bcdf0ab2a9efdfe9a7e90e9d3',
 
   # 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: 9c704aeef5c5521f7d42513ad159671c
+Signature: 464e0a927ae2cf2e85121380d019acc7
 
 ====================================================================================================
 LIBRARY: angle