am 84a357bb: Refactoring SIP classes to get ready for API review.

Merge commit '84a357bb6a8005e1c5e924e96a8ecf310e77c47c' into gingerbread-plus-aosp

* commit '84a357bb6a8005e1c5e924e96a8ecf310e77c47c':
  Refactoring SIP classes to get ready for API review.