https://developer.mozilla.org/en-US/docs/Web/API/VRDisplay/getLayers
VRDisplay: getLayers() method - Web APIs | MDN
The getLayers() method of the VRDisplay interface returns the layers currently being presented by the VRDisplay.
web apismethodmdn
https://bugzilla.mozilla.org/show_bug.cgi?id=1351681
1351681 - When ovr_SubmitFrame fails, VRDisplay.requestAnimationFrame runs unthrottled
RESOLVED (kearwood) in Core - WebVR. Last updated 2017-05-31.
ovrfailsrequestanimationframeruns