Report Login.SuccessReason in LoginPerformer

chromeos/login/auth/auth_status_consumer.h

Index: chromeos/login/auth/auth_status_consumer.h
diff --git a/chromeos/login/auth/auth_status_consumer.h b/chromeos/login/auth/auth_status_consumer.h
index 0c1158b3c66a62c2a47d007f9494ba3065c4ee9e..29b0eebcab91d1a33d319afc60df1e37522371a7 100644
--- a/chromeos/login/auth/auth_status_consumer.h
+++ b/chromeos/login/auth/auth_status_consumer.h
@@ -105,6 +105,14 @@ class CHROMEOS_EXPORT AuthFailure {
   GoogleServiceAuthError error_;
 };
 
+// Enum used for UMA. Do NOT reorder or remove entry. Don't forget to
+// update histograms.xml when adding new entries.
+enum SuccessReason {
+  OFFLINE_AND_ONLINE = 0,
+  OFFLINE_ONLY = 1,
+  NUM_SUCCESS_REASONS,  // This has to be the last item.
+};
+
 // An interface that defines the callbacks for objects that the
 // Authenticator class will call to report the success/failure of
 // authentication for Chromium OS.