Objects that derive from RefCounted/RefCountedThreadSafe should not have public dtors.

base/sequenced_task_runner.h

Index: base/sequenced_task_runner.h
diff --git a/base/sequenced_task_runner.h b/base/sequenced_task_runner.h
index f44b622e7781ca84a56c60eafdeaa658efc9a706..0db9128fe47dc8c0e9622c94687175cf14657f71 100644
--- a/base/sequenced_task_runner.h
+++ b/base/sequenced_task_runner.h
@@ -143,7 +143,10 @@ class BASE_EXPORT SequencedTaskRunner : public TaskRunner {
             this, from_here, object);
   }
 
-private:
+ protected:
+  virtual ~SequencedTaskRunner() {}
+
+ private:
   template <class T, class R> friend class subtle::DeleteHelperInternal;
   template <class T, class R> friend class subtle::ReleaseHelperInternal;