Comment 6 for bug 1363112

The previous implementation worked, because originally we were using TMP folder for storing the app state data, and that used to be XDG_RUNTIME_DIR/confined/<appname>. But that had security issues as the tmp folder for the app on desktop is /tmp, which is publicly available. The same structure should be applied on desktops as on phone, i.e. under the runtime dir.

Checking the app launcher bugs I found this one: https://bugs.launchpad.net/ubuntu-app-launch/+bug/1276658

In here you can see that the TMP folder is created with the package name, which is "com.ubuntu.camera" for the Camera app:
http://bazaar.launchpad.net/~indicator-applet-developers/ubuntu-app-launch/trunk.14.10/view/head:/helpers.c#L512

So not setting the app name correctly won't let state file to be saved properly.

You can use the .deb packages I made from the MR above to test camera and gallery apps: https://launchpad.net/~ubuntu-sdk-team/+archive/ubuntu/testing/+build/6315632