Add the concept of a V8 extras exports object

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 4f16120df33ddbb4d096c4a3a33820b911986833..f1d23c4e927618ad41aab83e37fd8a5565832531 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -5492,6 +5492,14 @@ void Context::DetachGlobal() {
 }
 
 
+Local<v8::Object> Context::GetExtrasExportsObject() {
+  i::Handle<i::Context> context = Utils::OpenHandle(this);
+  i::Isolate* isolate = context->GetIsolate();
+  i::Handle<i::JSObject> exports(context->extras_exports_object(), isolate);
+  return Utils::ToLocal(exports);
+}
+
+
 void Context::AllowCodeGenerationFromStrings(bool allow) {
   i::Handle<i::Context> context = Utils::OpenHandle(this);
   i::Isolate* isolate = context->GetIsolate();