Add an API to create a detached global object

src/bootstrapper.h

Index: src/bootstrapper.h
diff --git a/src/bootstrapper.h b/src/bootstrapper.h
index 66a3d8ad027a1631ff9c7a28f11f23c6e930bad8..a4b5321139c2a6d4b1e33b3dd585e8dea5e36bd3 100644
--- a/src/bootstrapper.h
+++ b/src/bootstrapper.h
@@ -82,6 +82,9 @@ class Bootstrapper final {
       v8::ExtensionConfiguration* extensions, size_t context_snapshot_index,
       GlobalContextType context_type = FULL_CONTEXT);
 
+  Handle<JSGlobalProxy> NewDetachedGlobal(
+      v8::Local<v8::ObjectTemplate> global_object_template);
+
   // Detach the environment from its outer global object.
   void DetachGlobal(Handle<Context> env);