Add helper methods for skipping Dart VM native bodies.

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

Index: pkg/front_end/lib/src/fasta/parser/listener.dart
diff --git a/pkg/front_end/lib/src/fasta/parser/listener.dart b/pkg/front_end/lib/src/fasta/parser/listener.dart
index 757fa946ac676f96e57c2188ee2accfb10fcc5fe..01d30edeffe24a2644c90eefa5f1623c944d4348 100644
--- a/pkg/front_end/lib/src/fasta/parser/listener.dart
+++ b/pkg/front_end/lib/src/fasta/parser/listener.dart
@@ -406,6 +406,9 @@ class Listener {
     logEvent("Member");
   }
 
+  /// This event can be used to support non-compliant (with respect to Dart
+  /// Language Specification) Dart VM native clauses. See
+  /// [dart_vm_native.dart].
   Link<Token> handleMemberName(Link<Token> identifiers) => identifiers;
 
   /// Doesn't have a corresponding begin event, use [beginMember] instead.