Add a comment to IsInitialized() to discourage devs to call it

components/arc/arc_service_manager.h

Index: components/arc/arc_service_manager.h
diff --git a/components/arc/arc_service_manager.h b/components/arc/arc_service_manager.h
index 07cb10e635d84fd4ade99eff3fc813694f315503..369292ff9eae246be5fa0f4ae4ea821e8d1e85a6 100644
--- a/components/arc/arc_service_manager.h
+++ b/components/arc/arc_service_manager.h
@@ -51,6 +51,9 @@ class ArcServiceManager {
   static ArcServiceManager* Get();
 
   // Returns if the ARC Service Manager instance exists.
+  // DO NOT CALL THIS. This function is a dirty workaround for properly shutting
+  // down chrome/browser/chromeos/extensions/file_manager/event_router.cc, and
+  // will likely be removed in the future.
   static bool IsInitialized();
 
   void AddObserver(Observer* observer);