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

base/message_loop_proxy_impl.h

Index: base/message_loop_proxy_impl.h
diff --git a/base/message_loop_proxy_impl.h b/base/message_loop_proxy_impl.h
index 88e1d45ad9418af312e7938373b31c0c8a9219b3..140c244aa92a43dc48552d3bd53d57d6d851855c 100644
--- a/base/message_loop_proxy_impl.h
+++ b/base/message_loop_proxy_impl.h
@@ -16,11 +16,8 @@ namespace base {
 // A stock implementation of MessageLoopProxy that is created and managed by a
 // MessageLoop. For now a MessageLoopProxyImpl can only be created as part of a
 // MessageLoop.
-class BASE_EXPORT MessageLoopProxyImpl
-    : public MessageLoopProxy {
+class BASE_EXPORT MessageLoopProxyImpl : public MessageLoopProxy {
  public:
-  virtual ~MessageLoopProxyImpl();
-
   // MessageLoopProxy implementation
   virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
                                const base::Closure& task,
@@ -39,11 +36,17 @@ class BASE_EXPORT MessageLoopProxyImpl
   virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
 
  protected:
+  virtual ~MessageLoopProxyImpl();
+
   // Override OnDestruct so that we can delete the object on the target message
   // loop if it still exists.
   virtual void OnDestruct() const OVERRIDE;
 
  private:
+  // Allow the MessageLoop to create a MessageLoopProxyImpl.
+  friend class ::MessageLoop;
+  friend class DeleteHelper<MessageLoopProxyImpl>;
+
   MessageLoopProxyImpl();
 
   // Called directly by MessageLoop::~MessageLoop.
@@ -55,9 +58,6 @@ class BASE_EXPORT MessageLoopProxyImpl
                       base::TimeDelta delay,
                       bool nestable);
 
-  // Allow the messageLoop to create a MessageLoopProxyImpl.
-  friend class ::MessageLoop;
-
   // The lock that protects access to target_message_loop_.
   mutable base::Lock message_loop_lock_;
   MessageLoop* target_message_loop_;