  v8::Local<v8::Value> GetFirstChild(v8::Isolate* isolate) {
    content::RenderFrame* render_frame;
    if (!MaybeGetRenderFrame(isolate, "firstChild", &render_frame))
      return v8::Null(isolate);

    blink::WebFrame* frame = render_frame->GetWebFrame()->FirstChild();
    return CreateWebFrameRenderer(isolate, frame);
  }
  v8::Local<v8::Value> GetFirstChild(v8::Isolate* isolate) {
    content::RenderFrame* render_frame;
    if (!MaybeGetRenderFrame(isolate, "firstChild", &render_frame))
      return v8::Null(isolate);

    blink::WebFrame* frame = render_frame->GetWebFrame()->FirstChild();
    return CreateWebFrameRenderer(isolate, frame);
  }