Parse optional and named parameters.

pkg/front_end/lib/src/fasta/source/outline_builder.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library fasta.outline_builder;
 
 import 'package:kernel/ast.dart' show
     AsyncMarker,
     ProcedureKind;
 
@@ skipping 354 matching lines @@
     push(popList(count) ?? NullValue.TypeVariables);
   }
 
   @override
   void handleVoidKeyword(Token token) {
     debugEvent("VoidKeyword");
     push(library.addVoidType(token.charOffset));
   }
 
   @override
-  void endFormalParameter(Token thisKeyword) {
+  void endFormalParameter(Token thisKeyword, FormalParameterType kind) {
     debugEvent("FormalParameter");
     String name = pop();
     TypeBuilder type = pop();
     int modifiers = Modifier.validate(pop());
     List<MetadataBuilder> metadata = pop();
     // TODO(ahe): Needs begin token.
     push(library.addFormalParameter(metadata, modifiers, type, name,
              thisKeyword != null, thisKeyword?.charOffset ?? -1));
   }
 
   @override
   void handleValuedFormalParameter(Token equals, Token token) {
     debugEvent("ValuedFormalParameter");
     // Ignored for now.
   }
 
   @override
+  void handleFormalParameterWithoutValue(Token token) {
+    debugEvent("FormalParameterWithoutValue");
+    // Ignored for now.
+  }
+
+  @override
   void endFunctionTypedFormalParameter(Token token) {
     debugEvent("FunctionTypedFormalParameter");
     pop(); // Function type parameters.
     pop(); // Type variables.
     String name = pop();
     pop(); // Return type.
     push(NullValue.Type);
     push(name);
   }
 
@@ skipping 213 matching lines @@
   Link<Token> handleMemberName(Link<Token> identifiers) {
     if (!isDartLibrary || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers);
   }
 
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }