That HTC group Google just bought? Here's their 2015 patent for a "portable electronic device" that includes a:
,,,switchable layer ... capable of being switched between a substantially opaque state and a substantially transparent state. The substantially opaque state prevents viewing of the optical element through the switchable layer and the substantially transparent state allows viewing of the optical element through the switchable layer.
Utilizing the portable electronic device of the embodiment of the invention, the optical unit (image sensor or light emitter) is disposed behind the front panel. Additionally, in the substantially opaque state, the optical unit is hidden and invisible. Therefore, the aesthetic appearance of the portable electronic device is improved.
The focus is on a:
.. conventional portable electronic device (smart phone), which comprises a housing, a camera and a flashlight ...However, the camera opening and the flashlight opening may not be aesthetically pleasing when applied to the conventional portable electronic device and thus, decreases the attraction of the portable electronic device to consumers.