code: func GerritBuildSet(c *pb.GerritChange) string {
  	return fmt.Sprintf("patch/gerrit/%s/%d/%d", c.Host, c.Change, c.Patchset)
  }
docs: // GerritBuildSet returns a buildset representation of c,
  // e.g. "patch/gerrit/chromium-review.googlesource.com/677784/5"