bool JoinNodeTransaction::CanDoIt() const {
  if (NS_WARN_IF(!mLeftNode) || NS_WARN_IF(!mRightNode) ||
      NS_WARN_IF(!mEditorBase) || !mLeftNode->GetParentNode()) {
    return false;
  }
  return mEditorBase->IsModifiableNode(*mLeftNode->GetParentNode());
}
bool
DeleteTextTransaction::CanDoIt() const
{
  if (NS_WARN_IF(!mCharData) || NS_WARN_IF(!mEditorBase)) {
    return false;
  }
  return mEditorBase->IsModifiableNode(*mCharData);
}