Add support for showing debug info on documents.

Shorten debug: prefix to just dbg:
Allow user to pass 0 or 1 as boolean values.
Use DocumentInfo instance to read from cursor in DocumentHolders.
Pass DocumentInfo instance to IconHelper to reduce zillion args.
Eliminate unnecessary State object arg from bind method.
Rename isVirtualDocument isVirtual.
Remove two unused methods from DocumentInfo.
Remove unused grid dimensions.
Address linben's ViewMode comment from previous CL.

Change-Id: I1b0c826677b69a7eaee4ee97415816aaf191121a
20 files changed