function sendCmdDirectly(cmd, data, options, fakeSrc) {
  const bg = !COMMANDS_WITH_SRC.includes(cmd) && getBgPage();
  const bgCopy = bg && bg !== window && bg.deepCopy;
  if (!bgCopy) {
    return sendCmd(cmd, data, options);
  }
  if (fakeSrc) {
    fakeSrc = bgCopy(fakeSrc);
    fakeSrc.fake = true;
  }
  return bg.handleCommandMessage(bgCopy({ cmd, data }), fakeSrc).then(deepCopy);
}
Sends the command+data directly so it's synchronous and faster than sendCmd thanks to deepCopy.
WARNING! Make sure `cmd` handler doesn't use `src` or `cmd` is listed in COMMANDS_WITH_SRC.