2003256 - FirefoxProfileMigrator._getResourcesInternal can sync-write to prefs instead of returning resource with `migrate` function

Status: NEW

(Firefox :: Migration, task, P3)

Description

[:Gijs (he/him)]

https://searchfox.org/firefox-main/rev/7032b912c282da6b9b8219e779b2a441a27aaec9/browser/components/migration/FirefoxProfileMigrator.sys.mjs#266-272

This function is intended to just return the resources (bookmarks, history etc.) and not actually modify any profile information. I think that in practice, this flow is only taken when migrating as part of the startup sequence (given the conditional), in which case by the time we call this function there is no other user confirmation or something like that involved, so it's sort of fine - but we should probably fix it so other people changing the function don't get the mistaken impression that this is an appropriate time to write to prefs (as it generally wouldn't be).