GitHub now has an open source utility called Gcam Services Provider that allows you to use Google Camera from Pixel smartphones on devices without Google services. This can be useful both for owners of Huawei and HONOR gadgets with Huawei Mobile Services, and for users of third-party firmware with cut out “gapps”.
Gcam Services Provider is not the Google Camera itself, but a port of exclusively those Google services that are required for the application to work. Roughly speaking, the utility emulates only the most necessary components exclusively for the “Camera”. Gcam Services Provider is distributed as a standalone application, that is, the device does not need to be reflashed. The utility has no interface, but is displayed in the application drawer in case it needs to be removed.
Gcam Services Provider is available in two versions: “Basic” and “Photo”. The first provides everything you need for Google Camera to work, with the exception of the button to display the captured images in full size. The second adds this button, but this modification conflicts with Google Photos if it is installed on the smartphone. In other words, if the device has Google Photos, then you need to select the basic version of the port.