Add typedef AST node boilerplate.

pkg/kernel/lib/visitor.dart

Index: pkg/kernel/lib/visitor.dart
diff --git a/pkg/kernel/lib/visitor.dart b/pkg/kernel/lib/visitor.dart
index ed5ebee4cfc3ceba2c7122937f9e56e9eb9eb2bc..f61d12e514ca744b2c1d801a90b41e0c8b2c6abf 100644
--- a/pkg/kernel/lib/visitor.dart
+++ b/pkg/kernel/lib/visitor.dart
@@ -221,6 +221,7 @@ class TreeVisitor<R>
   // Other tree nodes
   R visitLibrary(Library node) => defaultTreeNode(node);
   R visitDeferredImport(DeferredImport node) => defaultTreeNode(node);
+  R visitTypedef(Typedef node) => defaultTreeNode(node);
   R visitTypeParameter(TypeParameter node) => defaultTreeNode(node);
   R visitFunctionNode(FunctionNode node) => defaultTreeNode(node);
   R visitArguments(Arguments node) => defaultTreeNode(node);
@@ -242,6 +243,7 @@ class DartTypeVisitor<R> {
   R visitVectorType(VectorType node) => defaultDartType(node);
   R visitFunctionType(FunctionType node) => defaultDartType(node);
   R visitTypeParameterType(TypeParameterType node) => defaultDartType(node);
+  R visitTypedefType(TypedefType node) => defaultDartType(node);
 }
 
 class MemberReferenceVisitor<R> {
@@ -268,9 +270,11 @@ class Visitor<R> extends TreeVisitor<R>
   R visitVectorType(VectorType node) => defaultDartType(node);
   R visitFunctionType(FunctionType node) => defaultDartType(node);
   R visitTypeParameterType(TypeParameterType node) => defaultDartType(node);
+  R visitTypedefType(TypedefType node) => defaultDartType(node);
 
   // Class references
   R visitClassReference(Class node) => null;
+  R visitTypedefReference(Typedef node) => null;
 
   // Member references
   R defaultMemberReference(Member node) => null;