if (rebuild)
if (layoutDirty) {
  protected void layout(int width, int height)  {    boolean rebuild = false;    int flowAxis = getFlowAxis();    if (flowAxis == X_AXIS)      {        rebuild = !(width == layoutSpan);        layoutSpan = width;      }    else      {        rebuild = !(height == layoutSpan);        layoutSpan = height;      }    if (rebuild)      strategy.layout(this);    // TODO: If the span along the box axis has changed in the process of    // relayouting the rows (that is, if rows have been added or removed),    // call preferenceChanged in order to throw away cached layout information    // of the surrounding BoxView.    super.layout(width, height);  }