Revert of Assert sequence validity on non-thread-safe RefCount manipulations (2)

ppapi/shared_impl/tracked_callback.cc

Index: ppapi/shared_impl/tracked_callback.cc
diff --git a/ppapi/shared_impl/tracked_callback.cc b/ppapi/shared_impl/tracked_callback.cc
index 8c38c6241c160bbaa890d42ffecaf26c96d51e44..8a689dd1d65680ebc1eb7d0e033d6f591b9d0ed7 100644
--- a/ppapi/shared_impl/tracked_callback.cc
+++ b/ppapi/shared_impl/tracked_callback.cc
@@ -228,11 +228,6 @@
   if (resource_id_)
     tracker_->Remove(thiz);
   tracker_ = NULL;
-
-  // Relax the cross-thread access restriction to non-thread-safe RefCount.
-  // |lock_| protects the access to Resource instances.
-  base::ScopedAllowCrossThreadRefCountAccess
-      allow_cross_thread_ref_count_access;
   target_loop_ = NULL;
 }