NS_IMETHODIMP nsTreeBoxObject::GetView(nsITreeView * *aView)
{
  if (!mTreeBody) {
    if (!GetTreeBody()) {
      // Don't return an uninitialised view
      *aView = nsnull;
      return NS_OK;
    }

    if (mView)
      // Our new frame needs to initialise itself
      return mTreeBody->GetView(aView);
  }
  if (!mView) {
    nsCOMPtr<nsIDOMXULElement> xulele = do_QueryInterface(mContent);
    if (xulele) {
      // See if there is a XUL tree builder associated with the element
      nsCOMPtr<nsIXULTemplateBuilder> builder;
      xulele->GetBuilder(getter_AddRefs(builder));
      mView = do_QueryInterface(builder);

      if (!mView) {
        // No tree builder, create a tree content view.
        nsresult rv = NS_NewTreeContentView(getter_AddRefs(mView));
        NS_ENSURE_SUCCESS(rv, rv);
      }

      // Initialise the frame and view
      mTreeBody->SetView(mView);
    }
  }
  NS_IF_ADDREF(*aView = mView);
  return NS_OK;
}

NS_IMETHODIMP nsTreeBoxObject::RowCountChanged(int32_t aIndex, int32_t aDelta)
{
  nsTreeBodyFrame* body = GetTreeBody();
  if (body)
    return body->RowCountChanged(aIndex, aDelta);
  return NS_OK;
}

NS_IMETHODIMP nsTreeBoxObject::InvalidateColumnRange(PRInt32 aStart, PRInt32 aEnd, nsITreeColumn* aCol)
{
  nsTreeBodyFrame* body = GetTreeBody();
  if (body)
    return body->InvalidateColumnRange(aStart, aEnd, aCol);
  return NS_OK;
}

NS_IMETHODIMP nsTreeBoxObject::GetPageLength(PRInt32 *_retval)
{
  nsITreeBoxObject* body = GetTreeBody();
  if (body)
    return body->GetPageLength(_retval);
  return NS_OK;
}

NS_IMETHODIMP
nsTreeContentView::SetTree(nsITreeBoxObject* aTree)
{
  ClearRows();

  mBoxObject = aTree;

  if (aTree && !mRoot) {
    // Get our root element
    nsCOMPtr<nsIBoxObject> boxObject = do_QueryInterface(mBoxObject);
    nsCOMPtr<nsIDOMElement> element;
    boxObject->GetElement(getter_AddRefs(element));

    mRoot = do_QueryInterface(element);
    NS_ENSURE_STATE(mRoot);

    // Add ourselves to document's observers.
    nsIDocument* document = mRoot->GetDocument();
    if (document) {
      document->AddObserver(this);
      mDocument = document;
    }

    nsCOMPtr<nsIDOMElement> bodyElement;
    mBoxObject->GetTreeBody(getter_AddRefs(bodyElement));
    if (bodyElement) {
      mBody = do_QueryInterface(bodyElement);
      int32_t index = 0;
      Serialize(mBody, -1, &index, mRows);
    }
  }

  return NS_OK;
}