Add 'user friendly' datastore API.

impl/memory/context.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 memory
 
 import (
         "errors"
         "sync"
 
-        rds "github.com/luci/gae/service/rawdatastore"
+        rds "github.com/luci/gae/service/datastore"
         "golang.org/x/net/context"
 )
 
 type memContextObj interface {
         sync.Locker
         canApplyTxn(m memContextObj) bool
         applyTxn(c context.Context, m memContextObj)
 
         endTxn()
         mkTxn(*rds.TransactionOptions) memContextObj
@@ skipping 129 matching lines @@
         txnMC.Lock()
         defer txnMC.Unlock()
 
         if curMC.canApplyTxn(txnMC) {
                 curMC.applyTxn(d.c, txnMC)
         } else {
                 return rds.ErrConcurrentTransaction
         }
         return nil
 }