augment_chat.js

;(function(A) {
  Liferay.on(
	'chatPortletReady',
	function(event) {
		var Chat = Liferay.Chat;

		Chat.ConversationPanel = Chat.Conversation;

		Chat.Conversation = function(){
			// code before constructor....
			Chat.Conversation.superclass.constructor.apply(this, arguments);
			// code after constructor...
		};

		A.extend(
			Chat.Conversation,
			Chat.ConversationPanel,
			{
				// custom methods
			}
		);
	}
);
}(AUI()));