Allow ${CERT_SAN_EMAIL} and ${CERT_SAN_UPN} in the ONC Identity field

chromeos/network/client_cert_util.h

Index: chromeos/network/client_cert_util.h
diff --git a/chromeos/network/client_cert_util.h b/chromeos/network/client_cert_util.h
index c1fd42bb599cf2116dff3097febdf0cb73f3c20b..6b4141343bff42a7d6fe72a6a79c9a3c980fd2bf 100644
--- a/chromeos/network/client_cert_util.h
+++ b/chromeos/network/client_cert_util.h
@@ -46,6 +46,9 @@ struct CHROMEOS_EXPORT ClientCertConfig {
 
   // If |client_cert_type| equals kPattern, this contains the pattern.
   CertificatePattern pattern;
+
+  // The value of kIdentity, to enable substitutions.
+  std::string policy_identity;
 };
 
 // Returns true only if any fields set in this pattern match exactly with