This reverts commit 455ba62b5d.
Reason for revert: Breaks tests on all targets
Bug: 196825541
Bug: 197570389
Change-Id: Ida6792a09c54dee46105b6b914a0dd1545bdf48d
Existing ContentObserver will cache values and overwrite
them when the value itself is modified or caller force
updates.
Bug: 149571513
Test: Wrote unit tests, mostly for caching logic.
Not meant to test ContentObserver contract for registering an
observer.
Change-Id: I12835f6c2be27ce17f65a55c51c4ef85c63b4487