docs: protected boolean addChild(final Widget child,
                                 final GVRSceneObject childRootSceneObject, final int index,
                                 boolean preventLayout) {
          final boolean added = addChildInner(child, childRootSceneObject, index);
          Log.d(Log.SUBSYSTEM.WIDGET, TAG, "addChild [%s] %b", child, added);
          if (added) {
              onTransformChanged();
              if (!preventLayout) {
                  invalidateAllLayouts();
                  requestLayout();
              }
          }
          return added;
      }