Fix tests from https://codereview.chromium.org/166143002/

Didn't account for test's usage of PrivateKey.
BUG=341500

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251476 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251476