Errors overriding GameViewportClient::Draw

Hi,
I’m overriding GameViewportClient::Draw, but there are some errors that I can’t solve:


Error	C2064	term does not evaluate to a function taking 0 arguments 


(referred to


FMatrix mat = View->ViewProjectionMatrix();)


Error	C2065	'StatPtr_STAT_UIDrawingTime': undeclared identifier		

Error	C2228	left of '.GetStatId' must have class/struct/union	

Error	C2512	'FScopeCycleCounter::FScopeCycleCounter': no appropriate default constructor available	

Can someone help?
Thanks.