Don't use nss_util in CertificateManagerModel::IsHardwareBacked.

net/cert/nss_cert_database.h

Index: net/cert/nss_cert_database.h
diff --git a/net/cert/nss_cert_database.h b/net/cert/nss_cert_database.h
index a5d7eb888b27b697a19c27c171cdf100dcb74155..4986e5176fea156dd19cfafd792be590d57293c8 100644
--- a/net/cert/nss_cert_database.h
+++ b/net/cert/nss_cert_database.h
@@ -178,6 +178,9 @@ class NET_EXPORT NSSCertDatabase {
   // Check whether cert is stored in a readonly slot.
   bool IsReadOnly(const X509Certificate* cert) const;
 
+  // Check whether cert is stored in a hardware slot.
+  bool IsHardwareBacked(const X509Certificate* cert) const;
+
   // Registers |observer| to receive notifications of certificate changes.  The
   // thread on which this is called is the thread on which |observer| will be
   // called back with notifications.