clean up supplemental software drawing on ICS

* don't allocate big bitmaps for offscreen conversations on ICS
* reduce the bitmap size to the view size (vs. screen size)
* handle OOM gracefully
* ensure the 'doAfter' action happens even for offscreen convos

Bug: 7373250
Change-Id: I976dc826bed83d5872802e6d656eff2f72f9ed3d
3 files changed