Track async state in parser.

pkg/front_end/lib/src/fasta/parser/class_member_parser.dart

Index: pkg/front_end/lib/src/fasta/parser/class_member_parser.dart
diff --git a/pkg/front_end/lib/src/fasta/parser/class_member_parser.dart b/pkg/front_end/lib/src/fasta/parser/class_member_parser.dart
index 7901df0542023217c4decdcfa35516a3c6428b07..23a4e4107f26487cf5762850b5fe4263f7406506 100644
--- a/pkg/front_end/lib/src/fasta/parser/class_member_parser.dart
+++ b/pkg/front_end/lib/src/fasta/parser/class_member_parser.dart
@@ -13,8 +13,7 @@ import 'parser.dart' show Parser;
 /// Parser similar to [TopLevelParser] but also parses class members (excluding
 /// their bodies).
 class ClassMemberParser extends Parser {
-  ClassMemberParser(Listener listener, {bool asyncAwaitKeywordsEnabled: false})
-      : super(listener, asyncAwaitKeywordsEnabled: asyncAwaitKeywordsEnabled);
+  ClassMemberParser(Listener listener) : super(listener);
 
   Token parseExpression(Token token) => skipExpression(token);