Use ASTVisitor as in new AST.

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

Index: compiler/java/com/google/dart/compiler/ast/DartVariable.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartVariable.java b/compiler/java/com/google/dart/compiler/ast/DartVariable.java
index 5ed960ec9ed0313545545ae7fe84d0de401996e6..dd328cb8d4aee6e53a4fe5d82da3f41e656d499a 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartVariable.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartVariable.java
@@ -41,24 +41,14 @@ public class DartVariable extends DartDeclaration<DartIdentifier> implements Has
   }
 
   @Override
-  public void traverse(DartVisitor v, DartContext ctx) {
-    if (v.visit(this, ctx)) {
-      if (value != null) {
-        value = becomeParentOf(v.accept(value));
-      }
-    }
-    v.endVisit(this, ctx);
-  }
-
-  @Override
-  public void visitChildren(DartPlainVisitor<?> visitor) {
+  public void visitChildren(ASTVisitor<?> visitor) {
     if (value != null) {
       value.accept(visitor);
     }
   }
 
   @Override
-  public <R> R accept(DartPlainVisitor<R> visitor) {
+  public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitVariable(this);
   }
 }