Add logs to have better information in enrollment flow

Currently there's no log on the device to understand when the enrollment
was completed. In the past there was
"Wizard screen exit code: ENTERPRISE_ENROLLMENT_COMPLETED" message but at
some point it was removed.

Also added a log for the case when we restart Chrome, so that we still have
information that enrollment was successful.

We need this information when investigating enterprise enrolled issues.

BUG=chromium:1011375
TEST=Manually enrolled the device and checked that we have the log

Change-Id: I917641840c99a6e93dbea6ccc674841032edff48
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864777Reviewed-by: Denis Kuznetsov <antrim@chromium.org>
Reviewed-by: Igor <igorcov@chromium.org>
Commit-Queue: Igor <igorcov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706876}

chrome/browser/chromeos/login/wizard_controller.cc

@@ -936,10 +936,14 @@ void WizardController::OnEnrollmentDone() {
           policy::EnrollmentConfig::MODE_RECOVERY ||
       prescribed_enrollment_config_.mode ==
           policy::EnrollmentConfig::MODE_ENROLLED_ROLLBACK) {
+    LOG(WARNING) << "Restart Chrome to pick up the policy changes";
     chrome::AttemptRestart();
     return;
   }
 
+  // We need a log to understand when the device finished enrollment.
+  VLOG(1) << "Enrollment done";
+
   if (KioskAppManager::Get()->IsAutoLaunchEnabled())
     AutoLaunchKioskApp();
   else