VmCameraMicManager shows notifications over fullscreen apps

Bug: b/167491603
Change-Id: If8b20895d281721fb35918ee943e5fadc83e5cd2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2620818
Commit-Queue: Jason Lin <lxj@google.com>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Jason Lin <lxj@google.com>
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841952}

chrome/browser/chromeos/camera_mic/vm_camera_mic_manager.cc

@@ -302,6 +302,8 @@ void VmCameraMicManager::OpenNotification(VmType vm, NotificationType type) {
   rich_notification_data.pinned = true;
   rich_notification_data.buttons.emplace_back(
       l10n_util::GetStringUTF16(IDS_INTERNAL_APP_SETTINGS));
+  rich_notification_data.fullscreen_visibility =
+      message_center::FullscreenVisibility::OVER_USER;
 
   message_center::Notification notification(
       message_center::NOTIFICATION_TYPE_SIMPLE, GetNotificationId(vm, type),