Roll Dart SDK from c61a081 to 2b8d00a (1 revision) (#21320)

https://dart.googlesource.com/sdk.git/+log/c61a0818e4bd..2b8d00ac48e7

2020-09-22 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.10.0-156.0.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 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/master/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -34,14 +34,14 @@ 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': 'c61a0818e4bda08b2fa9a81346abafcab9d4df8b',
+  'dart_revision': '2b8d00ac48e7b0b9b72e227db844256fbb87d11b',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
   'dart_args_tag': '1.6.0',
   'dart_boringssl_gen_rev': '429ccb1877f7987a6f3988228bc2440e61293499',
   'dart_boringssl_rev': '4dfd5af70191b068aebe567b8e29ce108cee85ce',
-  'dart_collection_rev': '583693680fc067e34ca5b72503df25e8b80579f9',
+  'dart_collection_rev': '65d3e58ee5289528ec280d361a67a631d65b3d7f',
   'dart_dart_style_tag': '1.3.7',
   'dart_http_retry_tag': '0.1.1',
   'dart_http_throttle_tag': '1.0.2',
@@ -163,7 +163,7 @@ deps = {
    Var('dart_git') + '/args.git' + '@' + Var('dart_args_tag'),
 
   'src/third_party/dart/third_party/pkg/async':
-   Var('dart_git') + '/async.git@128c461a97dbdbd9336ba000ba5a5c02e79b8651',
+   Var('dart_git') + '/async.git@3fedad22c6940650526a86adebbf2872b81c2805',
 
   'src/third_party/dart/third_party/pkg/bazel_worker':
    Var('dart_git') + '/bazel_worker.git@26680d5e249b249c7216ab2fed0ac8ed4ee285c5',

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 7ddcff81a2a5eaee91099332665cea6c
+Signature: f58a32a9b7d49316c9500bc956653761
 
 UNUSED LICENSES: