Update from chromium https://crrev.com/301725/

net/tools/quic/quic_epoll_connection_helper.h

 // 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.
 //
 // The Google-specific helper for QuicConnection which uses
 // EpollAlarm for alarms, and used an int fd_ for writing data.
 
 #ifndef NET_TOOLS_QUIC_QUIC_EPOLL_CONNECTION_HELPER_H_
 #define NET_TOOLS_QUIC_QUIC_EPOLL_CONNECTION_HELPER_H_
 
@@ skipping 15 matching lines @@
 namespace tools {
 
 class AckAlarm;
 class RetransmissionAlarm;
 class SendAlarm;
 class TimeoutAlarm;
 
 class QuicEpollConnectionHelper : public QuicConnectionHelperInterface {
  public:
   explicit QuicEpollConnectionHelper(EpollServer* eps);
-  virtual ~QuicEpollConnectionHelper();
+  ~QuicEpollConnectionHelper() override;
 
   // QuicEpollConnectionHelperInterface
-  virtual const QuicClock* GetClock() const override;
-  virtual QuicRandom* GetRandomGenerator() override;
-  virtual QuicAlarm* CreateAlarm(QuicAlarm::Delegate* delegate) override;
+  const QuicClock* GetClock() const override;
+  QuicRandom* GetRandomGenerator() override;
+  QuicAlarm* CreateAlarm(QuicAlarm::Delegate* delegate) override;
 
   EpollServer* epoll_server() { return epoll_server_; }
 
  private:
   friend class QuicConnectionPeer;
 
   EpollServer* epoll_server_;  // Not owned.
 
   const QuicEpollClock clock_;
   QuicRandom* random_generator_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicEpollConnectionHelper);
 };
 
 }  // namespace tools
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_EPOLL_CONNECTION_HELPER_H_