am 01451756: Merge "docs: revise and add documentation for backup APIs" into froyo

Merge commit '014517569f6378e90cd3b0b5a3f86dfa9b8bf942' into froyo-plus-aosp

* commit '014517569f6378e90cd3b0b5a3f86dfa9b8bf942':
  docs: revise and add documentation for backup APIs