Roll Dart SDK from 749ee4e to defd2ae (2 revisions)

https://dart.googlesource.com/sdk.git/+log/749ee4e9e053..defd2ae02a3f

2021-08-09 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.14.0-390.0.dev
2021-08-09 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.14.0-389.0.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 dart-vm-team@google.com,aaclarke@google.com on the revert to ensure that a human
is aware of the problem.

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

@@ -35,7 +35,7 @@ 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': '749ee4e9e053344524f1a29ad04571a4dfef3d35',
+  'dart_revision': 'defd2ae02a3fdd845b45da97497dcc5b0573d625',
 
   # 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: e2fd126030d914f33c35d4840c3f9b17
+Signature: a12a857e6d8f1d80c4b26b281b013116
 
 UNUSED LICENSES:
 
@@ -9906,6 +9906,8 @@ ORIGIN: ../../../third_party/dart/benchmarks/DartCLIStartup/dart/DartCLIStartup.
 TYPE: LicenseType.bsd
 FILE: ../../../third_party/dart/benchmarks/DartCLIStartup/dart/DartCLIStartup.dart
 FILE: ../../../third_party/dart/benchmarks/DartCLIStartup/dart2/DartCLIStartup.dart
+FILE: ../../../third_party/dart/benchmarks/IsolateFibonacci/dart/IsolateFibonacci.dart
+FILE: ../../../third_party/dart/benchmarks/IsolateFibonacci/dart2/IsolateFibonacci.dart
 FILE: ../../../third_party/dart/benchmarks/MapLookup/dart/MapLookup.dart
 FILE: ../../../third_party/dart/benchmarks/MapLookup/dart/maps.dart
 FILE: ../../../third_party/dart/benchmarks/MapLookup/dart2/MapLookup.dart