The system-wide /tmp is not accessible by strictly-confined snaps, so /tmp/chromium-home won't work either.
In any case this looks like a limitation hard-coded in snapd, which won't create $SNAP_USER_DATA if $HOME is not in /home. So this is not specific to the chromium snap. I'll add a snapd task to the bug.
As a workaround (I realize this is less than ideal), could you maybe create a user with a home directory in /home just for this purpose, and have have your server process run chromium as this user?
The system-wide /tmp is not accessible by strictly-confined snaps, so /tmp/chromium-home won't work either.
In any case this looks like a limitation hard-coded in snapd, which won't create $SNAP_USER_DATA if $HOME is not in /home. So this is not specific to the chromium snap. I'll add a snapd task to the bug.
As a workaround (I realize this is less than ideal), could you maybe create a user with a home directory in /home just for this purpose, and have have your server process run chromium as this user?