Refactory lock screen and screen saver.

src/screensaver/ScreenSaverWindow.h

@@ -30,8 +30,7 @@ class ScreenSaverWindow : public QWidget
 public:
     explicit ScreenSaverWindow(QWidget *aParent = nullptr);
     void play();
-    void stop(bool aIsStopLocker = false);
-    void startLocker();
+    void stop();
 
 protected:
     void mousePressEvent(QMouseEvent* aEvent);