am 44165848: Merge "Operate on bitmaps directly for live and mark checks." into gingerbread

Merge commit '4416584802dbda4ade8df7f81af84a73d6887049' into gingerbread-plus-aosp

* commit '4416584802dbda4ade8df7f81af84a73d6887049':
  Operate on bitmaps directly for live and mark checks.