Native context: install JS builtins via container object.

src/runtime/runtime-internal.cc

Index: src/runtime/runtime-internal.cc
diff --git a/src/runtime/runtime-internal.cc b/src/runtime/runtime-internal.cc
index d39a12cef46bbb372a86bd92dff480d8097d3969..57a10a39515602fad5c195a8819534d4da6f8b4c 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -44,6 +44,16 @@ RUNTIME_FUNCTION(Runtime_ImportExperimentalToRuntime) {
 }
 
 
+RUNTIME_FUNCTION(Runtime_InstallJSBuiltins) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, container, 0);
+  RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
+  Bootstrapper::InstallJSBuiltins(isolate, container);
+  return isolate->heap()->undefined_value();
+}
+
+
 RUNTIME_FUNCTION(Runtime_Throw) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);