am 7da2bf6c: am c2bb441a: Merge "Clean up and augment Atomic class.  Replace QuasiAtomic MemBars."

* commit '7da2bf6ca44d0b3e81d92bfa45d5d81b4ed0f16c':
  Clean up and augment Atomic class.  Replace QuasiAtomic MemBars.