Consistently use only one of virtual/OVERRIDE/FINAL.

src/ostreams.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_OSTREAMS_H_
 #define V8_OSTREAMS_H_
 
 #include <cstddef>
 #include <cstdio>
 #include <cstring>
 #include <ostream>  // NOLINT
 #include <streambuf>
 
 #include "include/v8config.h"
 #include "src/base/macros.h"
 
 namespace v8 {
 namespace internal {
 
 class OFStreamBase : public std::streambuf {
  protected:
   explicit OFStreamBase(FILE* f);
   virtual ~OFStreamBase();
 
-  virtual int_type sync() FINAL;
-  virtual int_type overflow(int_type c) FINAL;
+  int_type sync() FINAL;
+  int_type overflow(int_type c) FINAL;
 
  private:
   FILE* const f_;
 
   DISALLOW_COPY_AND_ASSIGN(OFStreamBase);
 };
 
 
 // An output stream writing to a file.
 class OFStream FINAL : private virtual OFStreamBase, public std::ostream {
@@ skipping 25 matching lines @@
 std::ostream& operator<<(std::ostream& os, const AsReversiblyEscapedUC16& c);
 
 // Writes the given character to the output escaping everything outside
 // of printable ASCII range.
 std::ostream& operator<<(std::ostream& os, const AsUC16& c);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OSTREAMS_H_