** Extend nsIObjectFrame with methods the instance owner needs to call (if any)
** Make the instance owner own a content node rather than a frame (probably)
** Provide method NS_NewPluginInstanceOwner or something. also takes care of Init
* Move that file to content (or, directly add it in content)
* ...
* Create the owner on the content node. Provide a method on nsIObjectFrame to tell it that the plugin instance owner changed. provide a method to get the current instance owner. (Similar to how nsIImageLoadingContent works)
= Plugins without frames =