Fix pinned Crostini apps disappearing on restore

This patch fixes LauncherControllerHelper::IsValidIDForCurrentUser to
handle Crostini apps, so that the restore process can correctly add
pinned Crostini apps.

TEST=Manually verified both the Terminal and installed Crostini apps
re-appear after reboot.

Bug: 839141
Change-Id: I09a40a9f24779b19a2b1bae1c21f9a33e0ae1708
Reviewed-on: https://chromium-review.googlesource.com/1043665Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555999}

chrome/browser/ui/ash/launcher/launcher_controller_helper.cc

@@ -170,6 +170,11 @@ bool LauncherControllerHelper::IsValidIDForCurrentUser(
   if (arc_prefs && arc_prefs->IsRegistered(id))
     return true;
 
+  crostini::CrostiniRegistryService* registry_service =
+      crostini::CrostiniRegistryServiceFactory::GetForProfile(profile_);
+  if (registry_service && registry_service->IsCrostiniShelfAppId(id))
+    return registry_service->GetRegistration(id) != nullptr;
+
   if (app_list::IsInternalApp(id))
     return true;