Android: Widgets' contents not updating properly

Widgets using raster windows don't seem to be updating their contents correctly on Android. In attached video of the combowidgetmapper example, few issues can be noticed:

• when typing into the text field on the top, text updates with delay (sometimes way longer delay than in the video), and once longer text has been entered, the upper half is still drawing white with the cursor, while the bottom half draws the text
• when clicking on the Next button, more white rectangles can be seen
• when clicking on the bigger text field with the addresses, window flashes black (TBF this is partly existing, but seems to be worse)
• when clicking on the combobox, first pop up is not drawn at all, after it is drawn it stays drawn even after closing it

The issue seems to be introduced by https://codereview.qt-project.org/c/qt/qtbase/+/516515, which modified how raster windows are handled in Qt Android. Previously, they were blitted onto QAndroidPlatformScreen's surface, after all windows have their own surface and flush via RHI.

Since the problems start also before opening the combo box, the problem does not appear to be limited to when there are multiple windows/surfaces present.

Tested on Android emulator on an Android API 30 x86_64 image (without Google APIs) from Android SDK manager, and on an OnePlus 12R with Android API 34.