Re-add metadata passthrough on Get operations

impl/prod/raw_datastore.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package prod
 
 import (
         ds "github.com/luci/gae/service/datastore"
         "github.com/luci/gae/service/info"
         "golang.org/x/net/context"
@@ skipping 81 matching lines @@
         return err
 }
 
 func (d rdsImpl) DeleteMulti(ks []ds.Key, cb ds.DeleteMultiCB) error {
         err := datastore.DeleteMulti(d, dsMF2R(ks))
         return idxCallbacker(err, len(ks), func(_ int, err error) {
                 cb(err)
         })
 }
 
-func (d rdsImpl) GetMulti(keys []ds.Key, cb ds.GetMultiCB) error {
+func (d rdsImpl) GetMulti(keys []ds.Key, _meta ds.MultiMetaGetter, cb ds.GetMultiCB) error {
         rkeys := dsMF2R(keys)
         vals := make([]datastore.PropertyLoadSaver, len(keys))
         for i := range keys {
                 vals[i] = &typeFilter{ds.PropertyMap{}}
         }
         err := datastore.GetMulti(d, rkeys, vals)
         return idxCallbacker(err, len(keys), func(idx int, err error) {
                 cb(vals[idx].(*typeFilter).pm, err)
         })
 }
@@ skipping 35 matching lines @@
                 if !cb(dsR2F(k), tf.pm, cfunc) {
                         return nil
                 }
         }
 }
 
 func (d rdsImpl) RunInTransaction(f func(c context.Context) error, opts *ds.TransactionOptions) error {
         ropts := (*datastore.TransactionOptions)(opts)
         return datastore.RunInTransaction(d, f, ropts)
 }