nsAccessible*
nsXULTreeItemAccessibleBase::GetSiblingAtOffset(PRInt32 aOffset,
                                                nsresult* aError) const
{
  if (aError)
    *aError = NS_OK; // fail peacefully

  return mParent->GetChildAt(IndexInParent() + aOffset);
}
PRUint32
nsHTMLAreaAccessible::StartOffset()
{
  // Image map accessible is not hypertext accessible therefore
  // StartOffset/EndOffset implementations of nsAccessible doesn't work here.
  // We return index in parent because image map contains area links only which
  // are embedded objects.
  // XXX: image map should be a hypertext accessible.
  return IndexInParent();
}
PRUint32
nsHTMLAreaAccessible::EndOffset()
{
  return IndexInParent() + 1;
}