NS_STYLE_OVERFLOW_HIDDEN);
nsIScrollable::Scrollbar_Never);
HTMLContentSink::StartLayout(){  if (mLayoutStarted) {    return;  }  mLayoutStarted = PR_TRUE;  mLastNotificationTime = PR_Now();  // If it's a frameset document then disable scrolling.  // Else, reset scrolling to default settings for this shell.  // This must happen before the initial reflow, when we create the root frame  nsCOMPtr<nsIScrollable> scrollableContainer = do_QueryInterface(mDocShell);  if (scrollableContainer) {    if (mFrameset) {      scrollableContainer->        SetCurrentScrollbarPreferences(nsIScrollable::ScrollOrientation_Y,                                       NS_STYLE_OVERFLOW_HIDDEN);      scrollableContainer->        SetCurrentScrollbarPreferences(nsIScrollable::ScrollOrientation_X,                                       NS_STYLE_OVERFLOW_HIDDEN);    } else {      scrollableContainer->ResetScrollbarPreferences();    }  }  nsContentSink::StartLayout(!!mFrameset);}