Standardize usage of virtual/override/final in net/

net/dns/address_sorter_posix.h

Index: net/dns/address_sorter_posix.h
diff --git a/net/dns/address_sorter_posix.h b/net/dns/address_sorter_posix.h
index ce3ffdb90fb2f2a18c171956c95ed178a18d976b..cae787f12bbf26b803cb854a67919f4c7d88dfb7 100644
--- a/net/dns/address_sorter_posix.h
+++ b/net/dns/address_sorter_posix.h
@@ -61,17 +61,17 @@ class NET_EXPORT_PRIVATE AddressSorterPosix
   typedef std::map<IPAddressNumber, SourceAddressInfo> SourceAddressMap;
 
   explicit AddressSorterPosix(ClientSocketFactory* socket_factory);
-  virtual ~AddressSorterPosix();
+  ~AddressSorterPosix() override;
 
   // AddressSorter:
-  virtual void Sort(const AddressList& list,
-                    const CallbackType& callback) const override;
+  void Sort(const AddressList& list,
+            const CallbackType& callback) const override;
 
  private:
   friend class AddressSorterPosixTest;
 
   // NetworkChangeNotifier::IPAddressObserver:
-  virtual void OnIPAddressChanged() override;
+  void OnIPAddressChanged() override;
 
   // Fills |info| with values for |address| from policy tables.
   void FillPolicy(const IPAddressNumber& address,