Update elements, nodes and visitors for serialization.

pkg/compiler/lib/src/elements/visitor.dart

Index: pkg/compiler/lib/src/elements/visitor.dart
diff --git a/pkg/compiler/lib/src/elements/visitor.dart b/pkg/compiler/lib/src/elements/visitor.dart
index b571e56469ed807d28f79d9be183a0da60b00e20..ddc83d86e380b9e0276f388601434d951ed33d6e 100644
--- a/pkg/compiler/lib/src/elements/visitor.dart
+++ b/pkg/compiler/lib/src/elements/visitor.dart
@@ -24,7 +24,7 @@ abstract class ElementVisitor<R, A> {
   R visitExportElement(ExportElement e, A arg) => null;
   R visitPrefixElement(PrefixElement e, A arg) => null;
   R visitTypedefElement(TypedefElement e, A arg) => null;
-  R visitVariableElement(VariableElement e, A arg) => null;
+  R visitLocalVariableElement(LocalVariableElement e, A arg) => null;
   R visitParameterElement(ParameterElement e, A arg) => null;
   R visitFormalElement(FormalElement e, A arg) => null;
   R visitFieldElement(FieldElement e, A arg) => null;
@@ -100,12 +100,16 @@ abstract class BaseElementVisitor<R, A> extends ElementVisitor<R, A> {
     return visitElement(e, arg);
   }
 
-  @override
   R visitVariableElement(VariableElement e, A arg) {
     return visitElement(e, arg);
   }
 
   @override
+  R visitLocalVariableElement(LocalVariableElement e, A arg) {
+    return visitVariableElement(e, arg);
+  }
+
+  @override
   R visitParameterElement(ParameterElement e, A arg) {
     return visitVariableElement(e, arg);
   }