Reland: Refactor current GAE abstraction library to be free of the SDK*

go/src/infra/gae/libs/gae/prod/context.go

Index: go/src/infra/gae/libs/gae/prod/context.go
diff --git a/go/src/infra/gae/libs/gae/prod/context.go b/go/src/infra/gae/libs/gae/prod/context.go
new file mode 100644
index 0000000000000000000000000000000000000000..337fce0759f0e41474c56166221a0bbead2aa91c
--- /dev/null
+++ b/go/src/infra/gae/libs/gae/prod/context.go
@@ -0,0 +1,23 @@
+// 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 (
+	"golang.org/x/net/context"
+)
+
+// Use adds implementations for the following gae interfaces to the
+// context:
+//   * gae.RawDatastore
+//   * gae.TaskQueue
+//   * gae.Memcache
+//   * gae.GlobalInfo
+//
+// These can be retrieved with the gae.Get functions.
+//
+// The implementations are all backed by the real appengine SDK functionality,
+func Use(c context.Context) context.Context {
+	return useRDS(useMC(useTQ(useGI(c))))
+}