[DataStore] Support backup data state computation

Bug: 325144964
Test: Manual tests
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:5847d50e7bcab7d45d03351df802fb1228226aa5)
Merged-In: I8ad4f2788f9f364eceb1bca841830e1f3a68fe77
Change-Id: I8ad4f2788f9f364eceb1bca841830e1f3a68fe77
1 file changed