When PWA is waiting to install an update on restart, app is broken if user goes offline before next launch #782
Description
This is a bit of an edge case, but I noticed (in Chrome on Android) that if the app is waiting for a restart to install a PWA update, and if the user exits the app, perhaps doesn't need to restart it right away, then in the meantime goes offline (flight mode) and then restarts the app, the app will go into an inconsistent state, attempting to update itself but unable to finish fetching the new version.
This is a problem with the PWA spec, not with the app. The solution might be to force an immediate refresh and update when a new PWA version is waiting (as signalled to the user in Configuration), perhaps with an option to prevent that. We currently do that with the Electron version straight after a user has upgraded the shell app, to avoid the user having to do two restarts after an Electron upgrade. Doing so in the PWA could help avoid a (rare) broken app when the user needs it most (i.e. when fully offline or without a network signal).