code: func FormatRepoURL(host, project string, auth bool) url.URL {
  	pathPrefix := ""
  	if auth {
  		pathPrefix = "/a"
  	}
  	return url.URL{
  		Scheme: "https",
  		Host:   host,
  		Path:   fmt.Sprintf("%s/%s", pathPrefix, project),
  	}
  }
docs: // FormatRepoURL returns a canonical gitiles URL of the repo.
  // If auth is true, the returned URL has "/a/" path prefix.
  // See also ParseRepoURL.