RenderFrameHostImpl* RenderFrameHostImpl::FromID(
    int process_id, int routing_id) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  RoutingIDFrameMap* frames = g_routing_id_frame_map.Pointer();
  RoutingIDFrameMap::iterator it = frames->find(
      RenderFrameHostID(process_id, routing_id));
  return it == frames->end() ? NULL : it->second;
}

Unknown