linux: add UMA stat for the file system where the prefs are stored

I'd like to see how common it is to use a network file system for
your home directory.  This would help evaluate how important it is
to support these users.

See also:
  http://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/b43d2905f079fa1c

Review URL: http://codereview.chromium.org/3187011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56786 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 1d01d411a1d7e2ef29adf072855eb561e4c34cf7
3 files changed
tree: e5d9584836823a6cc8b718c52524b2991e525c8c
  1. base/
  2. build/
  3. ipc/
  4. testing/