allow unit_tests to re-create service manager context.

content/browser/child_process_launcher.cc

Index: content/browser/child_process_launcher.cc
diff --git a/content/browser/child_process_launcher.cc b/content/browser/child_process_launcher.cc
index f57f26bab9ed21dd854dab8c53ee157a8cac92f5..60b0766834bb73f5e63bd2d4a5fbf21881e93f4a 100644
--- a/content/browser/child_process_launcher.cc
+++ b/content/browser/child_process_launcher.cc
@@ -159,6 +159,11 @@ void ChildProcessLauncher::SetRegisteredFilesForService(
       service_name, std::move(required_files));
 }
 
+// static
+void ChildProcessLauncher::ResetRegisteredFilesForTesting() {
+  ChildProcessLauncherHelper::ResetRegisteredFilesForTesting();
+}
+
 ChildProcessLauncher::Client* ChildProcessLauncher::ReplaceClientForTest(
     Client* client) {
   Client* ret = client_;