Allow mojo_runner to connect to arbitrary executables.

mojo/runner/child_process.mojom

Index: mojo/runner/child_process.mojom
diff --git a/mojo/runner/child_process.mojom b/mojo/runner/child_process.mojom
deleted file mode 100644
index ece1e6783115865e2fd3f1329cca1a7f0648fb6a..0000000000000000000000000000000000000000
--- a/mojo/runner/child_process.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.runner;
-
-import "mojo/application/public/interfaces/application.mojom";
-
-interface ChildController {
-  // Starts the app.
-  StartApp(mojo.Application& application_request) => (int32 result);
-
-  // Exits the child process now (with no cleanup), with the given exit code.
-  ExitNow(int32 exit_code);
-};