RefCounted types should not have public destructors

ipc/ipc_listener.h

Index: ipc/ipc_listener.h
diff --git a/ipc/ipc_listener.h b/ipc/ipc_listener.h
index 49c12287f56affa03fa247a87a7830b531180eaf..9189eec7d1100146feb82b435b79b1a28d888311 100644
--- a/ipc/ipc_listener.h
+++ b/ipc/ipc_listener.h
@@ -16,8 +16,6 @@ class Message;
 // Implemented by consumers of a Channel to receive messages.
 class IPC_EXPORT Listener {
  public:
-  virtual ~Listener() {}
-
   // Called when a message is received.  Returns true iff the message was
   // handled.
   virtual bool OnMessageReceived(const Message& message) = 0;
@@ -39,6 +37,9 @@ class IPC_EXPORT Listener {
   // has an error that causes the listening channel to close.
   virtual void OnChannelListenError() {}
 #endif  // OS_POSIX
+
+ protected:
+  virtual ~Listener() {}
 };
 
 }  // namespace IPC