Roll Dart SDK from bf7e9d1 to d551980 (6 revisions) (flutter#18551)

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': 'bf7e9d13d730a71bd05974cc083ba0016f9e1528',
+  'dart_revision': 'd551980ac9fceeac6fded2572d001eb4c9b4e406',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -229,7 +229,7 @@ deps = {
    Var('dart_git') + '/dart2js_info.git' + '@' + Var('dart_dart2js_info_tag'),
 
   'src/third_party/dart/third_party/pkg/dartdoc':
-   Var('dart_git') + '/dartdoc.git@v0.31.0',
+   Var('dart_git') + '/dartdoc.git@v0.32.0',
 
   'src/third_party/dart/third_party/pkg/ffi':
    Var('dart_git') + '/ffi.git' + '@' + Var('dart_ffi_tag'),

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 9ab6a6b95dad900c3e3ae81b83f282f1
+Signature: b11f017bc26d0ad5a7dd55c8fcc98b2a
 
 UNUSED LICENSES: