am 66f1c459: Merge "Update the documentation for content provider security." into gingerbread

Merge commit '66f1c459ac15d1dba1850cb30759500d35078f29' into gingerbread-plus-aosp

* commit '66f1c459ac15d1dba1850cb30759500d35078f29':
  Update the documentation for content provider security.