Standardize usage of virtual/override/final in net/

net/quic/quic_stream_factory.cc

Index: net/quic/quic_stream_factory.cc
diff --git a/net/quic/quic_stream_factory.cc b/net/quic/quic_stream_factory.cc
index 687ea4c8971ca7a4f5d116328a3b6a26b7c75fb9..dac30962cee147bbaa41fe623de3319da82edd5e 100644
--- a/net/quic/quic_stream_factory.cc
+++ b/net/quic/quic_stream_factory.cc
@@ -103,9 +103,9 @@ class DefaultPacketWriterFactory : public QuicConnection::PacketWriterFactory {
  public:
   explicit DefaultPacketWriterFactory(DatagramClientSocket* socket)
       : socket_(socket) {}
-  virtual ~DefaultPacketWriterFactory() {}
+  ~DefaultPacketWriterFactory() override {}
 
-  virtual QuicPacketWriter* Create(QuicConnection* connection) const override;
+  QuicPacketWriter* Create(QuicConnection* connection) const override;
 
  private:
   DatagramClientSocket* socket_;