+ simplify adding new callbacks on storage state
+ streamline lock story for ifs members
Bug: 183101753
Fixes: 183101753
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest PackageManagerServiceTest ChecksumsTest
Change-Id: I86fffa7101eeb42ebccca67ae7f5d133c1ab9dfa