tree 2c8cbf4f2a7e839e80af0dc3808c8813b3701284
parent ac244261c8abaaaab5cd24506dc464fb6d762043
author Daniel Rosenberg <drosen@google.com> 1538527244 -0700
committer Daniel Rosenberg <drosen@google.com> 1538606365 -0700

Add checkpointing support for A/B updates

This adds implicit rollback support during A/B style updates.
If you explicitly start a checkpoint with -1, needsRollback will
trigger if the update fails, and should be used if any additional
cleanup is needed that is not covered by A/B itself.

Test: All Checkpoint tests pass
Bug: 111020314
Change-Id: I88b4a1098c6bac4dc1438a54c8a8f59577a6c17b