[milo] remove unused code.

milo/appengine/model/revision.go

-// Copyright 2015 The LUCI Authors. All rights reserved.
-// Use of this source code is governed under the Apache License, Version 2.0
-// that can be found in the LICENSE file.
-
-package model
-
-import (
-        ds "github.com/luci/gae/service/datastore"
-
-        "golang.org/x/net/context"
-)
-
-// Repository represents a repository that a Revision belongs to.
-type Repository struct {
-        ds.Key
-}
-
-// GetRepository returns the repository object for a given repository URL.
-// TODO(martiniss): convert this to luci project name by 2016-01
-func GetRepository(c context.Context, repositoryURL string) *Repository {
-        return &Repository{
-                *ds.NewKey(c, "Repository", repositoryURL, 0, nil),
-        }
-}
-
-// GetRevision returns the corresponding Revision object for a particular
-// revision hash in this repository.
-func (r *Repository) GetRevision(c context.Context, digest string) (*Revision, error) {
-        rev := &Revision{
-                Digest:     digest,
-                Repository: &r.Key,
-        }
-
-        err := ds.Get(c, rev)
-        return rev, err
-}
-
-// RevisionMetadata is the metadata associated with a particular Revision.
-type RevisionMetadata struct {
-        // Message is the commit message for a Revision.
-        Message string
-}
-
-// Revision is a immutable reference to a version of the code in a given
-// repository at a given point in time.
-//
-// Note that currently revisions have no notion of branch. This will need to
-// change once we support Chromium.
-type Revision struct {
-        // Digest is the content hash which uniquely identifies this Revision, in the
-        // context of its repository.
-        Digest string `gae:"$id"`
-
-        // Repository is the repository this Revision is associated with. See the
-        // Repository struct for more info.
-        Repository *ds.Key `gae:"$parent"`
-
-        // Metadata is any metadata (commit message, files changed, etc.)
-        // associated with this Revision.
-        Metadata RevisionMetadata `gae:",noindex"`
-
-        // Committer is the email of the user who committed this change.
-        Committer string
-
-        // Generation is the generation number of this Revision. This is used to sort
-        // commits into a roughly time-based order, without using timestamps.
-        // See http://www.spinics.net/lists/git/msg161165.html for background.
-        Generation int
-}