Fix compilation of the standalone onc_validator.

This was forgotten during a refactoring.

BUG=NONE

Review URL: https://codereview.chromium.org/27481002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228902 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228902