nsIPageSequenceFrame* pageSequence = nsnull;   nsIFrame *rootFrame = FrameManager()->GetRootFrame(); nsIFrame* child = rootFrame->GetFirstChild(nsnull);  if (nsnull != child) {   nsIScrollableFrame* scrollable = nsnull; nsresult rv = child->QueryInterface(NS_GET_IID(nsIScrollableFrame), (void **)&scrollable); if (NS_SUCCEEDED(rv) && (nsnull != scrollable)) {  child = scrollable->GetScrolledFrame(); } else { if (mPresContext->Type() == nsPresContext::eContext_PrintPreview) { child = child->GetFirstChild(nsnull); } }   rv = child->QueryInterface(NS_GET_IID(nsIPageSequenceFrame), (void**)&pageSequence); NS_ASSERTION(NS_SUCCEEDED(rv),"Error: Could not find pageSequence!");  *aResult = pageSequence; return NS_OK;
*aResult = nsnull; nsIFrame* frame = mFrameConstructor->GetPageSequenceFrame(); if (frame) { CallQueryInterface(frame, aResult);
PresShell::GetPageSequenceFrame(nsIPageSequenceFrame** aResult) const{  NS_PRECONDITION(nsnull != aResult, "null ptr");  if (nsnull == aResult) {    return NS_ERROR_NULL_POINTER;  }  nsIPageSequenceFrame* pageSequence = nsnull;  // The page sequence frame is the child of the rootFrame  nsIFrame *rootFrame = FrameManager()->GetRootFrame();  nsIFrame* child = rootFrame->GetFirstChild(nsnull);  if (nsnull != child) {      // but the child could be wrapped in a scrollframe so lets check      nsIScrollableFrame* scrollable = nsnull;      nsresult rv = child->QueryInterface(NS_GET_IID(nsIScrollableFrame),                                          (void **)&scrollable);      if (NS_SUCCEEDED(rv) && (nsnull != scrollable)) {          // if it is then get the scrolled frame          child = scrollable->GetScrolledFrame();      } else {        if (mPresContext->Type() == nsPresContext::eContext_PrintPreview) {          child = child->GetFirstChild(nsnull);        }      }      // make sure the child is a pageSequence      rv = child->QueryInterface(NS_GET_IID(nsIPageSequenceFrame),                                 (void**)&pageSequence);      NS_ASSERTION(NS_SUCCEEDED(rv),"Error: Could not find pageSequence!");      *aResult = pageSequence;      return NS_OK;  }  *aResult = nsnull;  return NS_ERROR_FAILURE;}