Standardize usage of virtual/override/final in net/

net/quic/quic_server_packet_writer.h

Index: net/quic/quic_server_packet_writer.h
diff --git a/net/quic/quic_server_packet_writer.h b/net/quic/quic_server_packet_writer.h
index 15c946b39a076480514daa9c4d324712160e1068..2e4646db3cc2a72caa0ff0e7f6f3566628473658 100644
--- a/net/quic/quic_server_packet_writer.h
+++ b/net/quic/quic_server_packet_writer.h
@@ -26,7 +26,7 @@ class QuicServerPacketWriter : public QuicPacketWriter {
 
   QuicServerPacketWriter(UDPServerSocket* socket,
                          QuicBlockedWriterInterface* blocked_writer);
-  virtual ~QuicServerPacketWriter();
+  ~QuicServerPacketWriter() override;
 
   // Use this method to write packets rather than WritePacket:
   // QuicServerPacketWriter requires a callback to exist for every write, which
@@ -41,16 +41,17 @@ class QuicServerPacketWriter : public QuicPacketWriter {
   void OnWriteComplete(int rv);
 
   // QuicPacketWriter implementation:
-  virtual bool IsWriteBlockedDataBuffered() const override;
-  virtual bool IsWriteBlocked() const override;
-  virtual void SetWritable() override;
+  bool IsWriteBlockedDataBuffered() const override;
+  bool IsWriteBlocked() const override;
+  void SetWritable() override;
 
  protected:
   // Do not call WritePacket on its own -- use WritePacketWithCallback
-  virtual WriteResult WritePacket(const char* buffer,
-                                  size_t buf_len,
-                                  const IPAddressNumber& self_address,
-                                  const IPEndPoint& peer_address) override;
+  WriteResult WritePacket(const char* buffer,
+                          size_t buf_len,
+                          const IPAddressNumber& self_address,
+                          const IPEndPoint& peer_address) override;
+
  private:
   UDPServerSocket* socket_;