Trivial: Moved nested DSR functions to top-level

* Since the monolithic DOMPostProcessor got split up into
  individual files (long back), there is no need to use nested
  functions to limit scope of helpers.

Change-Id: If9476a487240dc1b43bf88c9ad764252b9ba1ed3
Minor tweaks, cleanup, documentation to DSR computation

Change-Id: Ibbd2d70b410007230014ef23e5f0095a0158a5aa
Merge "Trivial: Moved nested DSR functions to top-level"
Merge "Minor tweaks, cleanup, documentation to DSR computation"