Show host owner rather than xmpp login on the UI where available.

remoting/host/mac/me2me_preference_pane.mm

Index: remoting/host/mac/me2me_preference_pane.mm
diff --git a/remoting/host/mac/me2me_preference_pane.mm b/remoting/host/mac/me2me_preference_pane.mm
index 3d0879bcc60ab0a315d8de5674dae9e3ffd033f5..56cc235e847ee5920dc79c30f9be82a242e3adef 100644
--- a/remoting/host/mac/me2me_preference_pane.mm
+++ b/remoting/host/mac/me2me_preference_pane.mm
@@ -468,12 +468,15 @@ std::string JsonHostConfig::GetSerializedData() const {
 
   std::string email;
   if (config_.get()) {
-    bool result = config_->GetString(remoting::kXmppLoginConfigPath, &email);
-
-    // The config has already been checked by |IsConfigValid|.
+    bool result = config_->GetString(remoting::kHostOwnerConfigPath, &email);
     if (!result) {
-      [self showError];
-      return;
+      result = config_->GetString(remoting::kXmppLoginConfigPath, &email);
+
+      // The config has already been checked by |IsConfigValid|.
+      if (!result) {
+        [self showError];
+        return;
+      }
     }
   }
   [disable_view_ setEnabled:(is_pane_unlocked_ && is_service_running_ &&