While in general we pass around references to nsAString/nsACString, I don't think we normally store pointers to nsAString/nsACString requiring a delete after. Instead we generally use the nsString/nsCString/nsAutoString/nsAutoCString objects.
Bug 1868901 Comment 3 Edit History
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While in general we pass around references to nsAString/nsACString, I don't think we normally store pointers to nsAString/nsACString requiring a delete after. Instead we generally use the nsString/nsCString/nsAutoString/nsAutoCString objects when declaring the actual storage.