Use ASTVisitor as in new AST.

compiler/java/com/google/dart/compiler/parser/CommentPreservingParser.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.parser;
 
 import com.google.dart.compiler.DartCompilerListener;
 import com.google.dart.compiler.DartSource;
 import com.google.dart.compiler.Source;
 import com.google.dart.compiler.ast.DartComment;
 import com.google.dart.compiler.ast.DartDeclaration;
 import com.google.dart.compiler.ast.DartNode;
-import com.google.dart.compiler.ast.DartNodeTraverser;
+import com.google.dart.compiler.ast.ASTVisitor;
 import com.google.dart.compiler.ast.DartUnit;
 import com.google.dart.compiler.metrics.CompilerMetrics;
 import com.google.dart.compiler.util.DartSourceString;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 
 /**
@@ skipping 118 matching lines @@
     if (comments != null) {
       assignDartComments(unit, comments);
     }
 
     return unit;
   }
 
   private void assignDartComments(DartUnit unit, List<DartComment> comments) {
     // Collect the AST nodes in a list.
     final List<DartNode> astNodes = new ArrayList<DartNode>();
-    unit.accept(new DartNodeTraverser<DartNode>() {
+    unit.accept(new ASTVisitor<DartNode>() {
       @Override
       public DartNode visitDeclaration(DartDeclaration<?> node) {
         astNodes.add(node);
         return super.visitNode(node);
       }
     });
 
     // Collect all the nodes in one list.
     List<DartNode> nodes = new ArrayList<DartNode>();
 
@@ skipping 38 matching lines @@
         }
       }
     }
 
     return false;
   }
 
   private List<DartNode> getChildren(DartNode parent) {
     final List<DartNode> children = new ArrayList<DartNode>();
 
-    parent.visitChildren(new DartNodeTraverser<DartNode>() {
+    parent.visitChildren(new ASTVisitor<DartNode>() {
       @Override
       public DartNode visitNode(DartNode node) {
         children.add(node);
         return null;
       }
     });
 
     return children;
   }
 
@@ skipping 14 matching lines @@
    */
   private DartComment.Style getCommentStyle(String sourceString, int commentStart) {
     if (sourceString.charAt(commentStart + 1) == '/') {
       return DartComment.Style.END_OF_LINE;
     } else if (sourceString.charAt(commentStart + 2) == '*') {
       return DartComment.Style.DART_DOC;
     }
     return DartComment.Style.BLOCK;
   }
 }