This clean up removes the way the document was using the canvas item drawing as a state for the outline. This isn't needed per object since the input data does not change between SPItem iterations.
The final bool can be given directly from SPDesktop. This leads the SPDocument getItem API to be protected and only called from SPDesktop itself. There is more future refactoring which should remove item picking from SPDocument.
This cleanup is needed for the new rendering engine work.