Add support for FieldFormalParameter.

pkg/compiler/lib/src/parser/node_listener.dart

Index: pkg/compiler/lib/src/parser/node_listener.dart
diff --git a/pkg/compiler/lib/src/parser/node_listener.dart b/pkg/compiler/lib/src/parser/node_listener.dart
index b5cbad61da0b334b0f4874726239afca58218d09..903032baaad2ff3e3340a8cd11c66aeea16ff405 100644
--- a/pkg/compiler/lib/src/parser/node_listener.dart
+++ b/pkg/compiler/lib/src/parser/node_listener.dart
@@ -182,7 +182,7 @@ class NodeListener extends ElementListener {
   }
 
   @override
-  void endFormalParameter(Token thisKeyword) {
+  void endFormalParameter(Token thisKeyword, Token period) {
     Expression name = popNode();
     if (thisKeyword != null) {
       Identifier thisIdentifier = new Identifier(thisKeyword);