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

cloud_print/service/win/service_listener.h

Index: cloud_print/service/win/service_listener.h
diff --git a/cloud_print/service/win/service_listener.h b/cloud_print/service/win/service_listener.h
index c100167342a5ee463e08c59d8b8f4225ef489191..7344edd7739dc78fac3189c4ff49bd3d9bf164e4 100644
--- a/cloud_print/service/win/service_listener.h
+++ b/cloud_print/service/win/service_listener.h
@@ -23,10 +23,10 @@ class Channel;
 class ServiceListener : public IPC::Listener {
  public:
   explicit ServiceListener(const base::FilePath& user_data_dir);
-  virtual ~ServiceListener();
+  ~ServiceListener() override;
 
-  virtual bool OnMessageReceived(const IPC::Message& msg) override;
-  virtual void OnChannelConnected(int32 peer_pid) override;
+  bool OnMessageReceived(const IPC::Message& msg) override;
+  void OnChannelConnected(int32 peer_pid) override;
 
  private:
   void Disconnect();