WebEngineView crashes in destructor if QQmlApplicationEngine is a child of qApp

When setting the parent of QQmlApplicationEngine to the QGuiApplication instance, the application crashes on closing, if a WebEngineView is used in qml.

This issue can be reproduced by modifying the "quicknanobrowser" example (see attached "quicknanobrowser.diff" file).

Steps to reproduce:

• Modify the main.cpp as shown in the diff file.
• Build and run the application.
• Close the application.
• Crash occurs on destroying the QQuickWebEngineView.

See also the attached stacktrace.