Templatize AstVisitor with its subclass

src/parsing/rewriter.cc

Index: src/parsing/rewriter.cc
diff --git a/src/parsing/rewriter.cc b/src/parsing/rewriter.cc
index 09ee8f77f28bc92559ea2e9f19a2b7fc5cf7a823..9a7627e3094bfa663a1119e807602a7797c8fa8f 100644
--- a/src/parsing/rewriter.cc
+++ b/src/parsing/rewriter.cc
@@ -11,7 +11,7 @@
 namespace v8 {
 namespace internal {
 
-class Processor: public AstVisitor {
+class Processor final : public AstVisitor<Processor> {
  public:
   Processor(Isolate* isolate, Scope* scope, Variable* result,
             AstValueFactory* ast_value_factory)
@@ -37,8 +37,6 @@ class Processor: public AstVisitor {
     InitializeAstVisitor(parser->stack_limit());
   }
 
-  ~Processor() override {}
-
   void Process(ZoneList<Statement*>* statements);
   bool result_assigned() const { return result_assigned_; }
 
@@ -81,7 +79,7 @@ class Processor: public AstVisitor {
   AstNodeFactory factory_;
 
   // Node visitors.
-#define DEF_VISIT(type) void Visit##type(type* node) override;
+#define DEF_VISIT(type) void Visit##type(type* node);
   AST_NODE_LIST(DEF_VISIT)
 #undef DEF_VISIT