am 37f62206: am 40351ece: am 7350ff3d: Merge change 24631 into donut

Merge commit '37f62206236dbfe89c15990cd506e5e40dc256b2'

* commit '37f62206236dbfe89c15990cd506e5e40dc256b2':
  Minor changes to api levels doc and upgrading doc. Change Linux "tested on" to Hardy Heron.