Replace ChildController with ShellClientFactory

mojo/shell/runner/child/child_controller.mojom

Index: mojo/shell/runner/child/child_controller.mojom
diff --git a/mojo/shell/runner/child/child_controller.mojom b/mojo/shell/runner/child/child_controller.mojom
deleted file mode 100644
index f71c0d538f8c6f43588748568973d073a283774b..0000000000000000000000000000000000000000
--- a/mojo/shell/runner/child/child_controller.mojom
+++ /dev/null
@@ -1,15 +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.mojom;
-
-import "mojo/shell/public/interfaces/shell_client.mojom";
-
-interface ChildController {
-  // Starts the app.
-  StartApp(ShellClient& request) => (int32 result);
-
-  // Exits the child process now (with no cleanup), with the given exit code.
-  ExitNow(int32 exit_code);
-};