Roll Dart SDK from 04cf6ade9fc4 to 80288ca68c49 (6 revisions) (flutter#21909)

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': '04cf6ade9fc4fb960a6f43177ecc8b9a20805250',
+  'dart_revision': '80288ca68c49dcd97081db9fe35bb6b8b0713268',
 
   # 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: 5dc2e0ab64cbdb1da2ee2a1ab43ec2e4
+Signature: 6ecfde5ebea1b1e1d3f507a2d5f64e41
 
 UNUSED LICENSES:
 
@@ -10204,7 +10204,6 @@ FILE: ../../../third_party/dart/sdk/lib/io/socket.dart
 FILE: ../../../third_party/dart/sdk/lib/io/stdio.dart
 FILE: ../../../third_party/dart/sdk/lib/io/string_transformer.dart
 FILE: ../../../third_party/dart/sdk/lib/js/js.dart
-FILE: ../../../third_party/dart/sdk/lib/math/jenkins_smi_hash.dart
 FILE: ../../../third_party/dart/sdk/lib/math/point.dart
 FILE: ../../../third_party/dart/sdk/lib/math/rectangle.dart
 FILE: ../../../third_party/dart/sdk/lib/mirrors/mirrors.dart