RefCounted types should not have public destructors, delegate cleanup

ppapi/proxy/host_dispatcher.h

Index: ppapi/proxy/host_dispatcher.h
diff --git a/ppapi/proxy/host_dispatcher.h b/ppapi/proxy/host_dispatcher.h
index 6c4dd2d5bad7d8c46f6c4ecc2b111963654e2e10..da64467d2ed91ee8255eceb5f6f47a8c2ca56359 100644
--- a/ppapi/proxy/host_dispatcher.h
+++ b/ppapi/proxy/host_dispatcher.h
@@ -33,14 +33,15 @@ class PPAPI_PROXY_EXPORT HostDispatcher : public Dispatcher {
   // actually represents a stack of blocking messages.
   class SyncMessageStatusReceiver : public IPC::ChannelProxy::MessageFilter {
    public:
-    virtual ~SyncMessageStatusReceiver() {}
-
     // Notification that a sync message is about to be sent out.
     virtual void BeginBlockOnSyncMessage() = 0;
 
     // Notification that a sync message reply was received and the dispatcher
     // is no longer blocked on a sync message.
     virtual void EndBlockOnSyncMessage() = 0;
+
+   protected:
+    virtual ~SyncMessageStatusReceiver() {}
   };
 
   // Constructor for the renderer side. This will take a reference to the