Update elements, nodes and visitors for serialization.

pkg/compiler/lib/src/tree/unparser.dart

 // Copyright (c) 2012, 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.
 
 import '../tokens/token.dart' show BeginGroupToken, Token;
 import '../tokens/token_constants.dart' as Tokens
     show IDENTIFIER_TOKEN, KEYWORD_TOKEN, PLUS_TOKEN;
 import '../util/util.dart';
 import 'nodes.dart';
 
@@ skipping 621 matching lines @@
   }
 
   visitBreakStatement(BreakStatement node) {
     visitGotoStatement(node);
   }
 
   visitContinueStatement(ContinueStatement node) {
     visitGotoStatement(node);
   }
 
-  visitAsyncForIn(AsyncForIn node) {
-    write(node.awaitToken.value);
-    write(' ');
+  visitForIn(ForIn node) {
     write(node.forToken.value);
     space();
     write('(');
     visit(node.declaredIdentifier);
     write(' ');
     addToken(node.inToken);
     visit(node.expression);
     write(')');
     space();
     visit(node.body);
   }
 
+  visitAsyncForIn(AsyncForIn node) {
+    write(node.awaitToken.value);
+    write(' ');
+    visitForIn(node);
+  }
+
   visitSyncForIn(SyncForIn node) {
-    write(node.forToken.value);
-    space();
-    write('(');
-    visit(node.declaredIdentifier);
-    write(' ');
-    addToken(node.inToken);
-    visit(node.expression);
-    write(')');
-    space();
-    visit(node.body);
+    visitForIn(node);
   }
 
   visitLabel(Label node) {
     visit(node.identifier);
     write(node.colonToken.value);
   }
 
   visitLabeledStatement(LabeledStatement node) {
     visit(node.labels);
     visit(node.statement);
@@ skipping 223 matching lines @@
   }
 
   visitStatement(Statement node) {
     throw 'internal error'; // Should not be called.
   }
 
   visitStringNode(StringNode node) {
     throw 'internal error'; // Should not be called.
   }
 }