Consistently use only one of virtual/OVERRIDE/FINAL.

src/ast-this-access-visitor.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_THIS_ACCESS_VISITOR_H_
 #define V8_AST_THIS_ACCESS_VISITOR_H_
 #include "src/ast.h"
 
 namespace v8 {
 namespace internal {
 
 class AstThisAccessVisitor : public AstVisitor {
  public:
   explicit AstThisAccessVisitor(Zone* zone);
 
   bool UsesThis() { return uses_this_; }
 
-#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
+#define DECLARE_VISIT(type) void Visit##type(type* node) OVERRIDE;
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
  private:
   bool uses_this_;
 
   void VisitIfNotNull(AstNode* node) {
     if (node != NULL) Visit(node);
   }
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
   DISALLOW_COPY_AND_ASSIGN(AstThisAccessVisitor);
 };
 }
 }  // namespace v8::internal
 #endif  // V8_AST_THIS_ACCESS_VISITOR_H_