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

net/base/network_change_notifier_linux.h

Index: net/base/network_change_notifier_linux.h
diff --git a/net/base/network_change_notifier_linux.h b/net/base/network_change_notifier_linux.h
index 1e8a7ebe2453afabe8a8ef3927a1505f4694beff..5a0f6dff308afeca8d64b2fe21963a1e703086e0 100644
--- a/net/base/network_change_notifier_linux.h
+++ b/net/base/network_change_notifier_linux.h
@@ -22,14 +22,14 @@ class NET_EXPORT_PRIVATE NetworkChangeNotifierLinux
   class Thread;
 
   NetworkChangeNotifierLinux();
-  virtual ~NetworkChangeNotifierLinux();
+  ~NetworkChangeNotifierLinux() override;
   static NetworkChangeCalculatorParams NetworkChangeCalculatorParamsLinux();
 
   // NetworkChangeNotifier:
-  virtual ConnectionType GetCurrentConnectionType() const override;
+  ConnectionType GetCurrentConnectionType() const override;
 
-  virtual const internal::AddressTrackerLinux*
-      GetAddressTrackerInternal() const override;
+  const internal::AddressTrackerLinux* GetAddressTrackerInternal()
+      const override;
 
   // The thread used to listen for notifications.  This relays the notification
   // to the registered observers without posting back to the thread the object