Allow mojo_runner to connect to arbitrary executables.

mojo/runner/child/test_native_service.mojom

Index: mojo/runner/child/test_native_service.mojom
diff --git a/components/web_view/test_runner/public/interfaces/layout_test_runner.mojom b/mojo/runner/child/test_native_service.mojom
similarity index 61%
copy from components/web_view/test_runner/public/interfaces/layout_test_runner.mojom
copy to mojo/runner/child/test_native_service.mojom
index 22fdffaff13479b668df2cd1c157e83681778bc8..8fbc3c12ad5f5217fb258e4f7cb6f125153c87ed 100644
--- a/components/web_view/test_runner/public/interfaces/layout_test_runner.mojom
+++ b/mojo/runner/child/test_native_service.mojom
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module web_view;
+module mojo.runner.test;
 
-interface LayoutTestRunner {
-  TestFinished();
+interface TestNativeService {
+  Invert(bool from_driver) => (bool from_target);
 };