Use ASTVisitor as in new AST.

compiler/java/com/google/dart/compiler/ast/DartClass.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.compiler.ast;
 
 import com.google.dart.compiler.common.HasSymbol;
 import com.google.dart.compiler.common.Symbol;
 import com.google.dart.compiler.resolver.ClassElement;
 
@@ skipping 151 matching lines @@
   @Override
   public void setSymbol(Symbol symbol) {
     this.element = (ClassElement) symbol;
   }
 
   public DartStringLiteral getNativeName() {
     return nativeName;
   }
 
   @Override
-  public void traverse(DartVisitor v, DartContext ctx) {
-    if (v.visit(this, ctx)) {
-      if (superclass != null) {
-        superclass = becomeParentOf(v.accept(superclass));
-      }
-      v.acceptWithInsertRemove(this, getMembers());
-      if (getTypeParameters() != null) {
-        v.acceptWithInsertRemove(this, getTypeParameters());
-      }
-      if (getInterfaces() != null) {
-        v.acceptWithInsertRemove(this, getInterfaces());
-      }
-      if (defaultClass != null) {
-        defaultClass = becomeParentOf(v.accept(defaultClass));
-      }
-    }
-    v.endVisit(this, ctx);
-  }
-
-  @Override
-  public void visitChildren(DartPlainVisitor<?> visitor) {
+  public void visitChildren(ASTVisitor<?> visitor) {
     visitor.visit(typeParameters);
     if (superclass != null) {
       superclass.accept(visitor);
     }
     visitor.visit(interfaces);
     if (defaultClass != null) {
       defaultClass.accept(visitor);
     }
     visitor.visit(members);
   }
 
   @Override
-  public <R> R accept(DartPlainVisitor<R> visitor) {
+  public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitClass(this);
   }
 }