if (!aScrollbar)
nsIFrame* frame = nsnull; aScrollbar->GetFrame(&frame);  nsCOMPtr<nsIContent> content; frame->GetContent(getter_AddRefs(content));  PRBool old = PR_TRUE;  nsAutoString value;  if (NS_CONTENT_ATTR_HAS_VALUE == content->GetAttribute(kNameSpaceID_None, nsXULAtoms::collapsed, value)) old = PR_FALSE;  if (aVisible == old)
nsGfxScrollFrameInner::SetScrollbarVisibility(nsIBox* aScrollbar, PRBool aVisible){  if (!aScrollbar)    return;  nsCOMPtr<nsIScrollbarFrame> scrollbar(do_QueryInterface(aScrollbar));  if (scrollbar) {    // See if we have a mediator.    nsCOMPtr<nsIScrollbarMediator> mediator;    scrollbar->GetScrollbarMediator(getter_AddRefs(mediator));    if (mediator) {      // Inform the mediator of the visibility change.      mediator->VisibilityChanged(scrollbar, aVisible);    }  }}