(In reply to Steven Englehardt [:englehardt] from comment #2)
(In reply to Tom Ritter [:tjr] (OOTO until 5/1?) from comment #1)
Perhaps this is an artifact of FPI not including scheme?
Looks like this was partially caused by Bug 1630763. I just retested and localStorage no longer changes when a storage access permission was granted. We still see sessionStorage swapping out, but that will probably be fixed by Bug 1629707. Let's keep this open and revisit after Bug 1629707 lands.
I've re-tested this now that Bug 1629707 has landed and we do still see a swapping of the sessionStorage jar after a storage access exception is granted. I think this is inevitable based on the fix we settled on for sessionStorage under dFPI. We could consider special casing this when both DFPI and FPI are enabled. Instead, we've decided to figure out a path to disabling dFPI when FPI is active (Bug 1631676). Closing this in favor of that.