Mojo: re-organize public tests

mojo/public/tests/sample_factory.mojom

-// Copyright 2013 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.
-
-module sample {
-
-// This sample shows how handles to MessagePipes can be sent as both parameters
-// to methods as well as fields on structs.
-
-struct Request {
-  int32 x;
-  handle<message_pipe> pipe;
-};
-
-struct Response {
-  int32 x;
-  handle<message_pipe> pipe;
-};
-
-[Peer=FactoryClient]
-interface Factory {
-  void DoStuff(Request request, handle<message_pipe> pipe);
-};
-
-[Peer=Factory]
-interface FactoryClient {
-  void DidStuff(Response response, string text);
-};
-
-}  // module sample