code: func crrevRedirect(ctx context.Context, client *http.Client, query string) (redirect string, err error) {
  	// API Explorer for this API:
  	// https://cr-rev.appspot.com/_ah/api/explorer#p/crrev/v1/crrev.redirect.get
  	u := "https://cr-rev.appspot.com/_ah/api/crrev/v1/redirect/" + url.PathEscape(query)
  	res, err := ctxhttp.Get(ctx, client, u)
  	if err != nil {
  		return "", err
  	}
  	defer res.Body.Close()
  
  	if res.StatusCode != http.StatusOK {
  		return "", fmt.Errorf("%s", res.Status)
  	}
  
  	var body struct {
  		RedirectURL string `json:"redirect_url"`
  	}
  	switch err := json.NewDecoder(res.Body).Decode(&body); {
  	case err != nil:
  		return "", fmt.Errorf("decoding crrev.com response: %s", err)
  	case body.RedirectURL == "":
  		return "", fmt.Errorf("crrev.com redirected to nothing")
  	default:
  		return body.RedirectURL, nil
  	}
  }
docs: // crrevRedirect returns a URL that crrev.com redirects the query to.