Roll Dart SDK from ae768c81b213 to 6af7d0febb32 (2 revisions) (#24477)

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': 'ae768c81b213c126ee387e62c8ccecea13762094',
+  'dart_revision': '6af7d0febb324748df2fa71c455d4118d65af769',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -332,7 +332,7 @@ deps = {
    Var('dart_git') + '/watcher.git' + '@' + Var('dart_watcher_rev'),
 
   'src/third_party/dart/third_party/pkg/web_socket_channel':
-   Var('dart_git') + '/web_socket_channel.git@680358915e331fda823908234f80beba1ed4ec83',
+   Var('dart_git') + '/web_socket_channel.git@76931ea1b81ba71e8319330c35285d3e88566315',
 
   'src/third_party/dart/third_party/pkg/yaml':
    Var('dart_git') + '/yaml.git@2392d113b0104dd19358f2833a282f19e2d67c01',

ci/licenses_golden/licenses_third_party

-Signature: 49d73fbe6fe4351815f79b114354cd6e
+Signature: 595ed1fc8be2776e9703ce48409c16fa
 
 UNUSED LICENSES: