Don't use nss_util in CertificateManagerModel::IsHardwareBacked.

net/cert/nss_cert_database.cc

Index: net/cert/nss_cert_database.cc
diff --git a/net/cert/nss_cert_database.cc b/net/cert/nss_cert_database.cc
index 0ba139b89775871afc7a28727662c74809341b11..9c2a3f1ffc50e2ec278c88a2a74c90bced2b44b8 100644
--- a/net/cert/nss_cert_database.cc
+++ b/net/cert/nss_cert_database.cc
@@ -318,6 +318,11 @@ bool NSSCertDatabase::IsReadOnly(const X509Certificate* cert) const {
   return slot && PK11_IsReadOnly(slot);
 }
 
+bool NSSCertDatabase::IsHardwareBacked(const X509Certificate* cert) const {
+  PK11SlotInfo* slot = cert->os_cert_handle()->slot;
+  return slot && PK11_IsHW(slot);
+}
+
 void NSSCertDatabase::AddObserver(Observer* observer) {
   observer_list_->AddObserver(observer);
 }