fix enrollment UMA

Noticed that the enrollment UMA will be invoked through the
enrollment flow for offline demo mode. At least it shouldn't be
NOTREACHED(). Considering the situation, I believe it can be
handled as other normal enrollment.

BUG=835904
TEST=manually

Change-Id: I61d50258429f3c72132c29d58a6208736756e3d8
Reviewed-on: https://chromium-review.googlesource.com/1092092Reviewed-by: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569374}

chrome/browser/chromeos/login/enrollment/enrollment_uma.cc

@@ -25,6 +25,7 @@ void EnrollmentUMA(policy::MetricEnrollment sample,
     case policy::EnrollmentConfig::MODE_LOCAL_ADVERTISED:
     case policy::EnrollmentConfig::MODE_SERVER_ADVERTISED:
     case policy::EnrollmentConfig::MODE_ATTESTATION:
+    case policy::EnrollmentConfig::MODE_OFFLINE_DEMO:
       base::UmaHistogramSparse(kMetricEnrollment, sample);
       break;
     case policy::EnrollmentConfig::MODE_LOCAL_FORCED:
@@ -37,13 +38,6 @@ void EnrollmentUMA(policy::MetricEnrollment sample,
     case policy::EnrollmentConfig::MODE_RECOVERY:
       base::UmaHistogramSparse(kMetricEnrollmentRecovery, sample);
       break;
-    case policy::EnrollmentConfig::MODE_OFFLINE_DEMO:
-      // MODE_OFFLINE_DEMO is currently NOTREACHED(), since the normal
-      // enrollment flow (which invokes this function) shouldn't use this mode.
-      // TODO(mukai, agawronska): decide what needs to be done here.
-      // https://crbug.com/835904
-      NOTREACHED();
-      break;
     case policy::EnrollmentConfig::MODE_NONE:
       NOTREACHED();
       break;