Some OpenVR functions such as GetUint64TrackedDeviceProperty can take an optional pointer to be filled with error information. However, we currently don't pass in a pointer when we use these, such as at https://cs.chromium.org/chromium/src/device/vr/openvr/openvr_gamepad_helper.cc?dr&q=openvr_gamep&sq=package:chromium&g=0&l=79, instead using the default value of null.

It may be beneficial to add error checking, although the way we do polling may make it completely unnecessary.