Merge "Update VR HAL docs." into nyc-dev am: a7145d28d8
am: 6aa1d2f247

* commit '6aa1d2f247e2173b15f16e54a4f054457365d331':
  Update VR HAL docs.

Change-Id: I634ea5ab675005cea4b7b647e1349943771cac68