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

base/synchronization/waitable_event.h

Index: base/synchronization/waitable_event.h
diff --git a/base/synchronization/waitable_event.h b/base/synchronization/waitable_event.h
index 6c917015ea4322fc52026a5eb9369a4b082b548e..60cca62992e220ac4dc20f5cb4fb27de1c3b1115 100644
--- a/base/synchronization/waitable_event.h
+++ b/base/synchronization/waitable_event.h
@@ -145,7 +145,6 @@ class BASE_EXPORT WaitableEvent {
       public RefCountedThreadSafe<WaitableEventKernel> {
    public:
     WaitableEventKernel(bool manual_reset, bool initially_signaled);
-    virtual ~WaitableEventKernel();
 
     bool Dequeue(Waiter* waiter, void* tag);
 
@@ -153,6 +152,10 @@ class BASE_EXPORT WaitableEvent {
     const bool manual_reset_;
     bool signaled_;
     std::list<Waiter*> waiters_;
+
+   private:
+    friend class RefCountedThreadSafe<WaitableEventKernel>;
+    ~WaitableEventKernel();
   };
 
   typedef std::pair<WaitableEvent*, size_t> WaiterAndIndex;