RefCounted types should not have public destructors, delegate cleanup

ipc/ipc_message.h

Index: ipc/ipc_message.h
diff --git a/ipc/ipc_message.h b/ipc/ipc_message.h
index 2c85e42ab75877f1a558624a967ce24ee36d96b3..a7d5424204fad703f479553fdccf9064fe222293 100644
--- a/ipc/ipc_message.h
+++ b/ipc/ipc_message.h
@@ -42,13 +42,14 @@ class IPC_EXPORT Message : public Pickle {
   // Implemented by objects that can send IPC messages across a channel.
   class IPC_EXPORT Sender {
    public:
-    virtual ~Sender() {}
-
     // Sends the given IPC message.  The implementor takes ownership of the
     // given Message regardless of whether or not this method succeeds.  This
     // is done to make this method easier to use.  Returns true on success and
     // false otherwise.
     virtual bool Send(Message* msg) = 0;
+
+   protected:
+    virtual ~Sender() {}
   };
 
   enum PriorityValue {