QCamera frame transformation breaks when switching devices too fast

This one is a bit hard to replicate.

When switching camera device for QCamera, there is a short delay before the new camera-device becomes active. If the user performs another device switch before the pending device has become active, the camera will not be updated to the final device and will use the one that was previously pending, and it will have incorrect frame transformation. This can mean the camera ends up mirrored or upside down, depending on the configuration.

Steps to reproduce:

1. Have a Android-device with at least two camera-devices
2. Switch to another camera-device
3. Before the pending device-switch is done, switch to another camera-device

What do you expect to happen:
I expect the in-between pending camera-device activation to be cancelled, and be presented with a frame from the most recent camera-device-change. This frame should have the correct transformation applied.

What happens:
The QCamera does not send frames from the newest camera-device change. Often, the frame presented will also have incorrect transformation, leading to the image being upside-down or mirrored incorrectly.

Reproducibility: Roughly half the time