Add ClientCertStoreChromeOS which only returns the certs for a given user.

BUG=302125

Review URL: https://codereview.chromium.org/112533002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241080 0039d316-1c4b-4281-b951-d872f2087c98
12 files changed