Oculus Browser v5.7.9.146202809 black screen on resuming fullscreen VR

[anusha_lvr]

Hi (dev team),

Oculus Browser version 5.7.9.146202809 has introduced a serious regression. If you take the headset off when you were in fullscreen VR in the browser, you would get a black screen when you put the headset back on.

It does not auto recover how many times take it off and on. Least inconvenient way to recover is by pressing the back button on the headset while wearing it, which brings you out of fullscreen VR and then entering fullscreen again.

Following is the easiest way to reproduce it:

- Connect the phone to the Gear VR headset which should launch you into the lounge.

- Open `Internet` and navigate to https://aframe.io/aframe/examples (search "aframe examples") and choose an example. I used the example called `Composite`. (Direct link: https://aframe.io/aframe/examples/showcase/composite/)

- Click the cardboard icon on the bottom right corner in the screen to enter the fullscreen immersive mode, which should work fine.

- While still being in the fullscreen immersive mode, take the headset off and then put it back on. (The idling duration does not seem to matter; you can put it back on immediately.)

- You will be greeted by a Black screen!

Hope you fix it soon...