Change storage migration to use quota APIs.

New quota APIs are much faster than trying to measure manually, and
removing this last user of calculateDirectorySize() means we can
remove it once and for all.

(cherry picked from commit fc522c677d2bcb4835f799b39993c69f4c222e55)

Bug: 36056324
Test: builds, boots
Merged-In: Icdf774cff520a4b7ca6ec210b34a1c5ff85f8110
Change-Id: Icdf774cff520a4b7ca6ec210b34a1c5ff85f8110
1 file changed