Embed a mojo ApplicationManager in content/browser

content/test/test_service.mojom

Index: content/test/test_service.mojom
diff --git a/tools/clang/blink_gc_plugin/tests/traceimpl_omitted_trace.cpp b/content/test/test_service.mojom
similarity index 71%
copy from tools/clang/blink_gc_plugin/tests/traceimpl_omitted_trace.cpp
copy to content/test/test_service.mojom
index b6dc2dffe589999c1be755a4ecef4f7dfd55e6ff..a94f10ff41c9d0f6b5d551da312dfaadc671dd81 100644
--- a/tools/clang/blink_gc_plugin/tests/traceimpl_omitted_trace.cpp
+++ b/content/test/test_service.mojom
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "traceimpl_omitted_trace.h"
+module content;
 
-// Nothing to define here.
+interface TestService {
+  DoSomething() => ();
+};