b521feaed4
Per UX, default strings should have space between value and units resulting in "12.3 GB". Add a formatting variant that returns the various components for callers who want to build their own strings. For now there is only one mounted emulated volume at a time, and it's always the primary storage, so give it the default rootId to keep old Uris working. Change-Id: Ifcc72a91a6b397ee65dc92642153286186eb64ac