Support for function typed formal parameters.

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 937aa46481c96d306e35a0ee2bb2b973ee7e4258..7a94816195bfbe7f76171d92b9ceaea3e1e86a98 100644
--- a/pkg/front_end/lib/src/fasta/parser/listener.dart
+++ b/pkg/front_end/lib/src/fasta/parser/listener.dart
@@ -739,6 +739,13 @@ class Listener {
 
   void beginFunctionTypedFormalParameter(Token token) {}
 
+  /// Handle the end of a function typed formal parameter.  Substructures:
+  /// - metadata
+  /// - modifiers
+  /// - return type
+  /// - parameter name (simple identifier)
+  /// - type parameters
+  /// - formal parameters
   void endFunctionTypedFormalParameter(Token token) {
     logEvent("FunctionTypedFormalParameter");
   }