Standardize usage of virtual/override/final in net/

net/quic/crypto/quic_random.cc

 // Copyright (c) 2012 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.
 
 #include "net/quic/crypto/quic_random.h"
 
 #include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "crypto/random.h"
 
 namespace net {
 
 namespace {
 
 class DefaultRandom : public QuicRandom {
  public:
   static DefaultRandom* GetInstance();
 
   // QuicRandom implementation
-  virtual void RandBytes(void* data, size_t len) override;
-  virtual uint64 RandUint64() override;
-  virtual void Reseed(const void* additional_entropy,
-                      size_t entropy_len) override;
+  void RandBytes(void* data, size_t len) override;
+  uint64 RandUint64() override;
+  void Reseed(const void* additional_entropy, size_t entropy_len) override;
 
  private:
   DefaultRandom() {};
-  virtual ~DefaultRandom() {}
+  ~DefaultRandom() override {}
 
   friend struct DefaultSingletonTraits<DefaultRandom>;
   DISALLOW_COPY_AND_ASSIGN(DefaultRandom);
 };
 
 DefaultRandom* DefaultRandom::GetInstance() {
   return Singleton<DefaultRandom>::get();
 }
 
 void DefaultRandom::RandBytes(void* data, size_t len) {
   crypto::RandBytes(data, len);
 }
 
 uint64 DefaultRandom::RandUint64() {
   uint64 value;
   RandBytes(&value, sizeof(value));
   return value;
 }
 
 void DefaultRandom::Reseed(const void* additional_entropy, size_t entropy_len) {
   // No such function exists in crypto/random.h.
 }
 
 }  // namespace
 
 // static
 QuicRandom* QuicRandom::GetInstance() { return DefaultRandom::GetInstance(); }
 
 }  // namespace net