Support for file listing in privet local filesystem

List files locally using privet.

BUG=338868

Review URL: https://codereview.chromium.org/141703022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251936 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251936