Chromad: Show encryption error during authentication

BUG=chromium:831128
TEST=manual
TBR=alemate@chromium.org

Change-Id: Ib9368a9ba657b381601086357abf4b766ef7b984
Reviewed-on: https://chromium-review.googlesource.com/1112240Reviewed-by: Lutz Justen <ljusten@chromium.org>
Commit-Queue: Roman Sorokin <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570006}

chrome/app/chromeos_strings.grdp

@@ -4333,6 +4333,9 @@
   <message name="IDS_AD_JOIN_CONFIG_NOT_PARSED" desc="Alert message to say unlocked configuration could not be parsed.">
     Oops!  Can't parse domain join configuration. Please contact your administrator.
   </message>
+  <message name="IDS_AD_AUTH_NOT_SUPPORTED_ENCRYPTION" desc="Alert message that user could not sign in due to not supported encryption types.">
+    Failed to login. The server does not support specified Kerberos encryption types. Please contact your administrator.
+  </message>
   <message name="IDS_AD_AUTH_UNKNOWN_ERROR" desc="Error message to show that occurs something a user could not fix.">
     Oops!  An unknown error occurred. Please try again later or contact your administrator if the issue persists.
   </message>

chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc

@@ -250,6 +250,8 @@ std::string GetAdErrorMessage(authpolicy::ErrorType error) {
   switch (error) {
     case authpolicy::ERROR_NETWORK_PROBLEM:
       return l10n_util::GetStringUTF8(IDS_AD_AUTH_NETWORK_ERROR);
+    case authpolicy::ERROR_KDC_DOES_NOT_SUPPORT_ENCRYPTION_TYPE:
+      return l10n_util::GetStringUTF8(IDS_AD_AUTH_NOT_SUPPORTED_ENCRYPTION);
     default:
       DLOG(WARNING) << "Unhandled error code: " << error;
       return l10n_util::GetStringUTF8(IDS_AD_AUTH_UNKNOWN_ERROR);