Use ASTVisitor as in new AST.

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

Index: compiler/java/com/google/dart/compiler/ast/DartBlock.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartBlock.java b/compiler/java/com/google/dart/compiler/ast/DartBlock.java
index 151c6d7ac2c24a78d76f1622ab1068d90af867a0..a081dfeaa1d0f4d2031f1b6faf1ac73574dd823b 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartBlock.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartBlock.java
@@ -32,20 +32,12 @@ public class DartBlock extends DartStatement {
   }
 
   @Override
-  public void traverse(DartVisitor v, DartContext ctx) {
-    if (v.visit(this, ctx)) {
-      v.acceptWithInsertRemove(this, stmts);
-    }
-    v.endVisit(this, ctx);
-  }
-
-  @Override
-  public void visitChildren(DartPlainVisitor<?> visitor) {
+  public void visitChildren(ASTVisitor<?> visitor) {
     visitor.visit(stmts);
   }
 
   @Override
-  public <R> R accept(DartPlainVisitor<R> visitor) {
+  public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitBlock(this);
   }
 }