if (!view) return nsnull;  nsIScrollableView* scrollingView;
nsGfxScrollFrameInner::GetScrollableView(nsIPresContext* aPresContext){  nsIScrollableView* scrollingView;  nsIView*           view;  nsIFrame* frame = nsnull;  mScrollAreaBox->GetFrame(&frame);  frame->GetView(aPresContext, &view);  nsresult result = view->QueryInterface(NS_GET_IID(nsIScrollableView), (void**)&scrollingView);  NS_ASSERTION(NS_SUCCEEDED(result), "assertion gfx scrollframe does not contain a scrollframe");            return scrollingView;}