Merge changes I17d87bae,Ie975e591,I6880b9b9,Ic752c7f3 into sc-dev

* changes:
  Add a TEST_MAPPING (9/n)
  Fix insufficient synchronization (8/n)
  Fix a race in the callback (7/n)
  setExplicitHealthCheckEnabled() needs to set mSyncRequired (6/n)