self if it isn't there... This lets us update all children before
sending them down the pipe...
set the size properly...
make FSDirectory have proper order for inheritance, so the Item
checkUpdate doesn't get called instead of the FSObject's
[git-p4: depot-paths = "//depot/": change = 767]
when directories and files change size, and update the proper
information..
hmm.. just realized we may still need to checkUpdate on all the
children we return, and that's better than always checkUpdate'ing
on add...
[git-p4: depot-paths = "//depot/": change = 766]