Make NSSCertDatabase::ListCerts work async on a worker thread.

chromeos/network/onc/onc_certificate_importer_impl.cc

Index: chromeos/network/onc/onc_certificate_importer_impl.cc
diff --git a/chromeos/network/onc/onc_certificate_importer_impl.cc b/chromeos/network/onc/onc_certificate_importer_impl.cc
index 4e466262b453dfe00d4ad8e0316b5b3f8c447357..636ecaa99339749ffcb5094b5245c5cdd7a87860 100644
--- a/chromeos/network/onc/onc_certificate_importer_impl.cc
+++ b/chromeos/network/onc/onc_certificate_importer_impl.cc
@@ -78,7 +78,8 @@ bool CertificateImporterImpl::ParseAndStoreCertificates(
 void CertificateImporterImpl::ListCertsWithNickname(const std::string& label,
                                                 net::CertificateList* result) {
   net::CertificateList all_certs;
-  net::NSSCertDatabase::GetInstance()->ListCerts(&all_certs);
+  // TODO(tbarzic): Use async |ListCerts|.
+  net::NSSCertDatabase::GetInstance()->ListCertsSync(&all_certs);
   result->clear();
   for (net::CertificateList::iterator iter = all_certs.begin();
        iter != all_certs.end(); ++iter) {