Remove mojo/shell and (most) service implementations

mojo/shell/app_child_process.mojom

Index: mojo/shell/app_child_process.mojom
diff --git a/mojo/shell/app_child_process.mojom b/mojo/shell/app_child_process.mojom
deleted file mode 100644
index d8cef1200a2eb28f00d5d9b6ea5593a506735847..0000000000000000000000000000000000000000
--- a/mojo/shell/app_child_process.mojom
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2014 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 mojo.shell {
-
-[Client=AppChildControllerClient]
-interface AppChildController {
-  // TODO(vtl): |service| should be of a more specific type.
-  StartApp(string? app_path, handle<message_pipe>? service);
-};
-
-interface AppChildControllerClient {
-  AppCompleted(int32 result);
-};
-
-}  // module mojo.shell