Consistently use only one of virtual/OVERRIDE/FINAL.

src/prettyprinter.h

 // Copyright 2012 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_PRETTYPRINTER_H_
 #define V8_PRETTYPRINTER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 
@@ skipping 12 matching lines @@
   const char* Print(AstNode* node);
   const char* PrintExpression(FunctionLiteral* program);
   const char* PrintProgram(FunctionLiteral* program);
 
   void Print(const char* format, ...);
 
   // Print a node to stdout.
   static void PrintOut(Zone* zone, AstNode* node);
 
   // Individual nodes
-#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:
   char* output_;  // output string buffer
   int size_;  // output_ size
   int pos_;  // current printing position
 
  protected:
   void Init();
@@ skipping 47 matching lines @@
   void dec_indent() { indent_--; }
 
   int indent_;
 };
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_PRETTYPRINTER_H_