nspresshell.cpp:

if (viewManager)
{ nsIFrame* focusFrame;
mPresContext->EventStateManager()->GetEventTarget(&focusFrame);
if (!focusFrame) { return nsnull; }
nsIView *aView;
aView = focusFrame->GetView();
nsIScrollableView *scrollView;
scrollView = aView->GetNearestScrollingView();
//result = viewManager->GetRootScrollableView(&scrollView);
if (NS_SUCCEEDED(result) && scrollView)