am 29332971: Merge "Add javadoc for display orientation." into gingerbread

Merge commit '29332971ddbace4ae3d645a67f28f717df8b1dbd' into gingerbread-plus-aosp

* commit '29332971ddbace4ae3d645a67f28f717df8b1dbd':
  Add javadoc for display orientation.