allow unit_tests to re-create service manager context.

content/browser/child_process_launcher_helper_mac.cc

Index: content/browser/child_process_launcher_helper_mac.cc
diff --git a/content/browser/child_process_launcher_helper_mac.cc b/content/browser/child_process_launcher_helper_mac.cc
index 0e435086af02f91b74fe1dcecb2405fb182536f5..0b1d4a6fd334accdde9fcbd47d98a5e37daefaeb 100644
--- a/content/browser/child_process_launcher_helper_mac.cc
+++ b/content/browser/child_process_launcher_helper_mac.cc
@@ -158,6 +158,9 @@ void ChildProcessLauncherHelper::SetRegisteredFilesForService(
 }
 
 // static
+void ChildProcessLauncherHelper::ResetRegisteredFilesForTesting() {}
+
+// static
 base::File OpenFileToShare(const base::FilePath& path,
                            base::MemoryMappedFile::Region* region) {
   // Not used yet (until required files are described in the service manifest on