Refactor X509Certificate caching to cache the OS handle, rather than the X509Certificate

net/base/cert_database_nss.cc

Index: net/base/cert_database_nss.cc
diff --git a/net/base/cert_database_nss.cc b/net/base/cert_database_nss.cc
index a32a7a3923c80578759b1c2ee73d02179bfbc6cc..3b30586b7adfaa24568b2c5704d2ee5fdb0bbee0 100644
--- a/net/base/cert_database_nss.cc
+++ b/net/base/cert_database_nss.cc
@@ -99,9 +99,7 @@ void CertDatabase::ListCerts(CertificateList* certs) {
        !CERT_LIST_END(node, cert_list);
        node = CERT_LIST_NEXT(node)) {
     certs->push_back(X509Certificate::CreateFromHandle(
-        node->cert,
-        X509Certificate::SOURCE_LONE_CERT_IMPORT,
-        X509Certificate::OSCertHandles()));
+        node->cert, X509Certificate::OSCertHandles()));
   }
   CERT_DestroyCertList(cert_list);
 }