Chrome OS: remove user type notification for child users.

TBR=alemate@chromium.org

(cherry picked from commit 869e6b7c4cb3954868a0874eeeceea3b276c9fd4)

Bug: 813923
Change-Id: Ibf3f07c2f98922bb85023dc601dbf213ff91379b
Reviewed-on: https://chromium-review.googlesource.com/938577
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#540005}
Reviewed-on: https://chromium-review.googlesource.com/945423
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#645}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
diff --git a/ash/system/supervised/tray_supervised_user.cc b/ash/system/supervised/tray_supervised_user.cc
index ea73d59..a56563e 100644
--- a/ash/system/supervised/tray_supervised_user.cc
+++ b/ash/system/supervised/tray_supervised_user.cc
@@ -100,6 +100,11 @@
 }
 
 void TraySupervisedUser::CreateOrUpdateNotification() {
+  // No notification for the child user.
+  if (Shell::Get()->session_controller()->IsUserChild())
+    return;
+
+  // Regular supervised user.
   std::unique_ptr<Notification> notification =
       Notification::CreateSystemNotification(
           message_center::NOTIFICATION_TYPE_SIMPLE, kNotificationId,