Standardize usage of virtual/override/final in net/

net/quic/quic_connection_helper.h

Index: net/quic/quic_connection_helper.h
diff --git a/net/quic/quic_connection_helper.h b/net/quic/quic_connection_helper.h
index e1754e5e4e1a43b7ea081a6d47e96eee6afc2cc4..140bf9aac5c04a1f2f207dd18380a000720cc51a 100644
--- a/net/quic/quic_connection_helper.h
+++ b/net/quic/quic_connection_helper.h
@@ -34,12 +34,12 @@ class NET_EXPORT_PRIVATE QuicConnectionHelper
   QuicConnectionHelper(base::TaskRunner* task_runner,
                        const QuicClock* clock,
                        QuicRandom* random_generator);
-  virtual ~QuicConnectionHelper();
+  ~QuicConnectionHelper() override;
 
   // QuicConnectionHelperInterface
-  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;
 
  private:
   base::TaskRunner* task_runner_;