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

base/synchronization/waitable_event_watcher_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/synchronization/waitable_event_watcher.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/message_loop.h"
 #include "base/synchronization/lock.h"
@@ skipping 25 matching lines @@
     AutoLock locked(lock_);
     flag_ = true;
   }
 
   bool value() const {
     AutoLock locked(lock_);
     return flag_;
   }
 
  private:
+  friend class RefCountedThreadSafe<Flag>;
+  ~Flag() {}
+
   mutable Lock lock_;
   bool flag_;
+
+  DISALLOW_COPY_AND_ASSIGN(Flag);
 };
 
 // -----------------------------------------------------------------------------
 // This is an asynchronous waiter which posts a task to a MessageLoop when
 // fired. An AsyncWaiter may only be in a single wait-list.
 // -----------------------------------------------------------------------------
 class AsyncWaiter : public WaitableEvent::Waiter {
  public:
   AsyncWaiter(MessageLoop* message_loop,
               const base::Closure& callback,
@@ skipping 198 matching lines @@
 // -----------------------------------------------------------------------------
 // This is called when the MessageLoop which the callback will be run it is
 // deleted. We need to cancel the callback as if we had been deleted, but we
 // will still be deleted at some point in the future.
 // -----------------------------------------------------------------------------
 void WaitableEventWatcher::WillDestroyCurrentMessageLoop() {
   StopWatching();
 }
 
 }  // namespace base