This should be as simple as moving through monotonically increasing integers, just like DB migrations, taking cleanup actions at each step. We can trigger this in a background thread in onPause, or after delayed startup -- we can decide on "urgency" by looking at how big a gap we have to that integer. I can mentor this for an advanced contributor, or I'll attack it myself.

To remove: Periodic: * Stale crash reports: Bug 942612. One-time: * Cache directory: Bug 1045886 * netpredictions.sqlite*: Bug 1045884 * addons.sqlite, extensions.sqlite: Bug 966707 * Stale unsalted profiles: Bug 1015236 * Product Announcements prefs: Bug 1045278

We could also delete stale Sync profile prefs. If we wanted to do something a little more extensible, we could broadcast an intent and make it easy to implement a clean-up action off in some isolated component.

Could anyone elaborate about the bug, and what we need to do in the bug ? Also provide some mxr/dxr links if possible. Thanks!!

This is a pretty advanced bug, so be aware! Periodically we want to clean up some sets of files. This can be triggered by app lifecycle events combined with (range-checked) times. Once only, we want to delete another list of files. The best way to do that is a version step -- see, for example, the way ProfileInformationCache or BrowserDatabaseHelper works. We'd start at zero, have a destination of 1, and the 0->1 transition would involve deleting the things in Comment 1. The 'janitor' is the component that does these two things in response to lifecycle events and its own state.

bug 1238785 implemented a CleanupService that doesn't keep track of what it's deleted and always tries to delete everything. We could repurpose that code to be more intelligent here and do the remaining cleanup actions indicated above.

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