Strip vpn.openvpn.TLSAuthContents in chrome://policy.

chrome/browser/policy/configuration_policy_handler_chromeos.cc

Index: chrome/browser/policy/configuration_policy_handler_chromeos.cc
diff --git a/chrome/browser/policy/configuration_policy_handler_chromeos.cc b/chrome/browser/policy/configuration_policy_handler_chromeos.cc
index af17bc152a71e8f656068874aec9c85f590cf13d..4a45ca892030719375824c75ab8c149ccaadb5b4 100644
--- a/chrome/browser/policy/configuration_policy_handler_chromeos.cc
+++ b/chrome/browser/policy/configuration_policy_handler_chromeos.cc
@@ -123,6 +123,7 @@ void NetworkConfigurationPolicyHandler::MaskSensitiveValues(
     { onc::kVPN, onc::vpn::kIPsec, onc::vpn::kPSK },
     { onc::kVPN, onc::vpn::kL2TP, onc::vpn::kPassword },
     { onc::kVPN, onc::vpn::kOpenVPN, onc::vpn::kPassword },
+    { onc::kVPN, onc::vpn::kOpenVPN, onc::vpn::kTLSAuthContents },
     { onc::kWiFi, onc::wifi::kEAP, onc::eap::kPassword },
     { onc::kWiFi, onc::wifi::kPassphrase },
   };