Roll Dart SDK from e4c9b06 to a4e6fe1 (2 revisions) (#23006)

Author: skia-flutter-autoroll

DEPS

@@ -34,7 +34,7 @@ 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': 'e4c9b06267d32507ead537df60d5b17d1a1dcca6',
+  'dart_revision': 'a4e6fe145bf7c0939464ea49efbc1fe81c93e4ba',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -156,7 +156,7 @@ deps = {
   # WARNING: Unused Dart dependencies in the list below till "WARNING:" marker are removed automatically - see create_updated_flutter_deps.py.
 
   'src/third_party/dart/third_party/pkg/args':
-   Var('dart_git') + '/args.git@139140125126661fac88c9aa5882165936d01c91',
+   Var('dart_git') + '/args.git@6921e2f63796368bbe65a64ad943df84932dff55',
 
   'src/third_party/dart/third_party/pkg/async':
    Var('dart_git') + '/async.git@695b3ac280f107c84adf7488743abfdfaaeea68f',
@@ -183,7 +183,7 @@ deps = {
    Var('dart_git') + '/convert.git@6513985a1b1ea8a0b987fbef699250ce2cdc3cca',
 
   'src/third_party/dart/third_party/pkg/crypto':
-   Var('dart_git') + '/crypto.git@a5ec902dda5a635a35c6b363ec64458cf84c5872',
+   Var('dart_git') + '/crypto.git@c89a5be0375875fe7ff71625fa2b79f5a421f06d',
 
   'src/third_party/dart/third_party/pkg/csslib':
    Var('dart_git') + '/csslib.git@6f77b3dcee957d3e2d5083f666221a220e9ed1f1',

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: def638709f28af418bf9bc2ff2b860bc
+Signature: 694aa0eb4934730ddf07b7cf0c36ebdf
 
 UNUSED LICENSES: