Move some field to optional for storage probing

BUG=none
TEST=manually test

Change-Id: I4cd4319369aa86e7dfbe6a7ddcf8d9376eb91661
Reviewed-on: https://gerrit.chromium.org/gerrit/64191
Reviewed-by: Katie Roberts-Hoffman <katierh@chromium.org>
Commit-Queue: Katie Roberts-Hoffman <katierh@chromium.org>
Tested-by: Katie Roberts-Hoffman <katierh@chromium.org>
1 file changed