Standardize usage of virtual/override/final in net/

net/quic/crypto/chacha20_poly1305_decrypter.h

 // Copyright 2014 The Chromium 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 NET_QUIC_CRYPTO_CHACHA20_POLY1305_DECRYPTER_H_
 #define NET_QUIC_CRYPTO_CHACHA20_POLY1305_DECRYPTER_H_
 
 #include "net/quic/crypto/aead_base_decrypter.h"
 
 namespace net {
 
 // A ChaCha20Poly1305Decrypter is a QuicDecrypter that implements the
 // AEAD_CHACHA20_POLY1305 algorithm specified in
 // draft-agl-tls-chacha20poly1305-04, except that it truncates the Poly1305
 // authenticator to 12 bytes. Create an instance by calling
 // QuicDecrypter::Create(kCC12).
 //
 // It uses an authentication tag of 16 bytes (128 bits). There is no
 // fixed nonce prefix.
 class NET_EXPORT_PRIVATE ChaCha20Poly1305Decrypter : public AeadBaseDecrypter {
  public:
   enum {
     kAuthTagSize = 12,
   };
 
   ChaCha20Poly1305Decrypter();
-  virtual ~ChaCha20Poly1305Decrypter();
+  ~ChaCha20Poly1305Decrypter() override;
 
   // Returns true if the underlying crypto library supports ChaCha20+Poly1305.
   static bool IsSupported();
 
 #if !defined(USE_OPENSSL)
  protected:
   // AeadBaseDecrypter methods:
   virtual void FillAeadParams(base::StringPiece nonce,
                               base::StringPiece associated_data,
                               size_t auth_tag_size,
                               AeadParams* aead_params) const override;
 #endif
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChaCha20Poly1305Decrypter);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CRYPTO_CHACHA20_POLY1305_DECRYPTER_H_