Use QWebEnginePage::isVisible from WebEnginePage::changeLifecycleState
WebEnginePage::changeLifecycleState can be called in situations when there's no view, so call QWebEnginePage::isVisible instead of using view()->isVisible()
WebEnginePage::changeLifecycleState can be called in situations when there's no view, so call QWebEnginePage::isVisible instead of using view()->isVisible()