A new version of the Google Daydream View VR headset (to complement the new Pixel phones) Google does have a 2016 patent for a head-mountable VR device with adjustable transparency. The device could be controlled via cell phone.
The remote device may be any type of computing device or transmitter including a laptop computer, a mobile telephone, or tablet computing device, etc., that is configured to transmit data to the device. The remote device and the device may contain hardware to enable the communication link, such as processors, transmitters, receivers, antennas, etc.
The optical element could include at least one liquid crystal cell, an electrochromic cell, a suspended particle device, and/or a switchable mirror. The optical element could be operable to change the transmittance of the optical element and/or the optics.
Review of current Daydream View headset.
At least we know that Google knows what SPD is.