Roll Dart SDK from 20bf2fcf5670 to cfeb1d647ae5 (22 revisions) (flutter#19752)

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': '20bf2fcf567074d087d977cfbfb469e7fe766023',
+  'dart_revision': 'cfeb1d647ae59220747a56bec6d19db53c1f1e7e',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -179,7 +179,7 @@ deps = {
    Var('dart_git') + '/boolean_selector.git@1309eabed510cc3b7536fd4367d39b97ebee3d69',
 
   'src/third_party/dart/third_party/pkg/charcode':
-   Var('dart_git') + '/charcode.git@9085e6b6127f084d66c0a94810a808121459012a',
+   Var('dart_git') + '/charcode.git@af1e2d59a9c383da94f99ea51dac4b93fb0626c4',
 
   'src/third_party/dart/third_party/pkg/cli_util':
    Var('dart_git') + '/[email protected]',

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 85932205c4f2a2abd9ccf1fb28e2a719
+Signature: 1ee74a07630558ba8c292ecfa0825e1d
 
 UNUSED LICENSES: