Update {virtual,override,final} to follow C++11 style in net.

net/android/network_change_notifier_android.cc

Index: net/android/network_change_notifier_android.cc
diff --git a/net/android/network_change_notifier_android.cc b/net/android/network_change_notifier_android.cc
index 0a109b81fac1b210daf214f6949b6fe68ec910f2..d1ad338a15f32f439fc7586d236a95eecc3cfd86 100644
--- a/net/android/network_change_notifier_android.cc
+++ b/net/android/network_change_notifier_android.cc
@@ -77,20 +77,16 @@ class NetworkChangeNotifierAndroid::DnsConfigServiceThread
                          // We're only interested in tunnel interface changes.
                          base::Bind(NotifyNetworkChangeNotifierObservers)) {}
 
-  virtual ~DnsConfigServiceThread() {
-    Stop();
-  }
+  ~DnsConfigServiceThread() override { Stop(); }
 
-  virtual void Init() override {
+  void Init() override {
     address_tracker_.Init();
     dns_config_service_ = DnsConfigService::CreateSystemService();
     dns_config_service_->WatchConfig(
         base::Bind(&NetworkChangeNotifier::SetDnsConfig));
   }
 
-  virtual void CleanUp() override {
-    dns_config_service_.reset();
-  }
+  void CleanUp() override { dns_config_service_.reset(); }
 
   static void NotifyNetworkChangeNotifierObservers() {
     NetworkChangeNotifier::NotifyObserversOfIPAddressChange();