In Scene3D, Qt3D viewport not correctly scaled for Retina/HiDPI displays

Using HiDPI, the content of Scene3D QML element is not correctly scaled, rather it is display at the bottom-left of it and clipped.

This bug is very easy to reproduce:
1. Take the example scene3d from qt3d examples
2. Enable HiDPI in main.cpp:
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
3. Run the example on a HiDPI display, you will see the problem

This bug seems close to bug QTBUG-45369, but affects Qt Quick embedding Qt3D content rather then C++ embedding Qt3D content.