Roll src/third_party/dart 09d22a0..77ac3d0 (14 commits) (flutter#13970)

dart-lang/sdk@77ac3d0a5c [vm/aot/tfa] Introduce TFA-specific representation of classes (refactoring)
dart-lang/sdk@3931d43d42 Issue 39407. Test for ListLiteral inference in presence of null(s).
dart-lang/sdk@28d272b3dd Move more types access / creation helpers into ElementsTypesMixin.
dart-lang/sdk@aff0915ead Fix BazelWorkspaces in which multiple 'bin' directories exist, e.g. on distributed build systems
dart-lang/sdk@fee8c5503c Mark the completion.registerLibraryPaths as deprecated in the Dart Analysis Server.
dart-lang/sdk@970c164826 [cfe] Use correct types in transformations and start verifying getStaticType
dart-lang/sdk@f979bd9899 Merge RestrictedAnalysisContext into AnalysisContextImpl.
dart-lang/sdk@f3455278ff Use 'isNonNullableByDefault' flag in TypeProviderImpl.
dart-lang/sdk@dcaf959589 Fix several unused elements, and unnecessary casts.
dart-lang/sdk@6646412705 Rewrite DEFERRED_IMPORT_OF_EXTENSION check to using ImportElement namespace.
dart-lang/sdk@b7de866bee [vm] Avoid holding canonical hashes at rest.
dart-lang/sdk@03676ad489 Remove AnalysisEngine.createAnalysisContext()
dart-lang/sdk@535cbf5db9 NNBD preview: Text for return type with nullable return type in subclass
dart-lang/sdk@af541cd0dd [VM/nnbd] Ignore nullability of type Never provided by CFE.

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': '09d22a0509b9bccdcf7dc1e00d1c577ec7eaa79f',
+  'dart_revision': '77ac3d0a5cadcecb00a68b0eb0001c9ef8fc5add',
 
   # 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: d84c3491eae16403a85e0414b4e22c71
+Signature: fe7ad83013a4b930b12500b844661f78
 
 UNUSED LICENSES: