am 19c4b29d: am 8310b42f: Add javadoc saying that wake locks are ref counted by default.

Merge commit '19c4b29d46aece70dbe532ba9078c904fbc62502'

* commit '19c4b29d46aece70dbe532ba9078c904fbc62502':
  Add javadoc saying that wake locks are ref counted by default.