Use ASTVisitor as in new AST.

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

Index: compiler/java/com/google/dart/compiler/ast/DartNativeDirective.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartNativeDirective.java b/compiler/java/com/google/dart/compiler/ast/DartNativeDirective.java
index 2780a984fb40a6894a6825c038aaeab778dc3495..96c968e9a63d62a6403cc7ab992a8220401a6417 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartNativeDirective.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartNativeDirective.java
@@ -19,20 +19,12 @@ public class DartNativeDirective extends DartDirective {
   }
 
   @Override
-  public void traverse(DartVisitor v, DartContext ctx) {
-    if (v.visit(this, ctx)) {
-      nativeUri = becomeParentOf(v.accept(nativeUri));
-    }
-    v.endVisit(this, ctx);
-  }
-
-  @Override
-  public void visitChildren(DartPlainVisitor<?> visitor) {
+  public void visitChildren(ASTVisitor<?> visitor) {
     nativeUri.accept(visitor);
   }
 
   @Override
-  public <R> R accept(DartPlainVisitor<R> visitor) {
+  public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitNativeDirective(this);
   }
 }