Add the concept of a V8 extras exports object

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index a434098cc0a316e331de0bef222f5b845bcc5a52..43d2c7447394e69e8f39a9720560ea45a4066f5c 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -21029,3 +21029,21 @@ TEST(SealHandleScopeNested) {
     USE(obj);
   }
 }
+
+
+TEST(ExtrasExportsObject) {
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope handle_scope(isolate);
+  LocalContext env;
+
+  // standalone.gypi ensures we include the test-extra.js file, which should
+  // add the testExtraShouldReturnFive export
+  v8::Local<v8::Object> exports = env->GetExtrasExportsObject();
+
+  auto func =
+      exports->Get(v8_str("testExtraShouldReturnFive")).As<v8::Function>();
+  auto undefined = v8::Undefined(isolate);
+  auto result = func->Call(undefined, 0, {}).As<v8::Number>();
+
+  CHECK(result->Value() == 5.0);
+}