code: func getBlame(c context.Context, host string, b *buildbucketpb.Build) ([]*ui.Commit, error) {
  	commit := b.GetInput().GetGitilesCommit()
  	// No commit? No blamelist.
  	if commit == nil {
  		return nil, nil
  	}
  	// TODO(hinoka): This converts a buildbucketpb.Commit into a string
  	// and back into a buildbucketpb.Commit.  That's a bit silly.
  	return simplisticBlamelist(c, &model.BuildSummary{
  		BuildKey:  MakeBuildKey(c, host, BuildAddress(b)),
  		BuildSet:  []string{protoutil.GitilesBuildSet(commit)},
  		BuilderID: BuilderID{BuilderID: *b.Builder}.String(),
  	})
  }
docs: // getBlame fetches blame information from Gitiles.
  // This requires the BuildSummary to be indexed in Milo.