Use ASTVisitor as in new AST.

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

Index: compiler/java/com/google/dart/compiler/ast/DartSyntheticErrorExpression.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartSyntheticErrorExpression.java b/compiler/java/com/google/dart/compiler/ast/DartSyntheticErrorExpression.java
index 9e6603e36e28655313c4d44240935486909b6580..d2d31b9df07955fe54511201653fd9ff44ac7921 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartSyntheticErrorExpression.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartSyntheticErrorExpression.java
@@ -19,7 +19,7 @@ public class DartSyntheticErrorExpression extends DartExpression {
   }
 
   @Override
-  public <R> R accept(DartPlainVisitor<R> visitor) {
+  public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitSyntheticErrorExpression(this);
   }
 
@@ -28,12 +28,6 @@ public class DartSyntheticErrorExpression extends DartExpression {
   }
 
   @Override
-  public void traverse(DartVisitor v, DartContext ctx) {
-    v.visit(this, ctx);
-    v.endVisit(this, ctx);
-  }
-
-  @Override
-  public void visitChildren(DartPlainVisitor<?> visitor) {
+  public void visitChildren(ASTVisitor<?> visitor) {
   }
 }