void RenderView::addChild(RenderObject* newChild, RenderObject* beforeChild) { // Seamless iframes are considered part of an enclosing render flow thread from the parent document. This is necessary for them to look // up regions in the parent document during layout. if (newChild && !newChild->isRenderFlowThread()) { RenderBox* seamlessBox = enclosingSeamlessRenderer(document()); if (seamlessBox && seamlessBox->flowThreadContainingBlock()) newChild->setFlowThreadState(seamlessBox->flowThreadState()); } RenderBlock::addChild(newChild, beforeChild); }