1. What happened
Gear VR player crashes when Anti Alias sampling is changed via script if Single Pass Stereo is used. If Multi Pass Stereo is used then the Anti Alias change is apparent and the crash does not occur.

2. How we can reproduce it using the example you attached
Open the attached project.
Build and run the scene on your Gear VR device.
After a few seconds the script will try to toggle the Anti Aliasing samples.
This crashes the player.
To see correct behaviour, try this again but use Multi Pass Stereo in Player settings.