Call JS functions via native context instead of js builtins object.

src/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var $observeEnqueueSpliceRecord;
 var $observeBeginPerformSplice;
 var $observeEndPerformSplice;
 
 var $observeObjectMethods;
 var $observeArrayMethods;
@@ skipping 685 matching lines @@
 var removePrototypeFn = function(f, i) {
   if (i % 2 === 1) %FunctionRemovePrototype(f);
 };
 $observeObjectMethods.forEach(removePrototypeFn);
 $observeArrayMethods.forEach(removePrototypeFn);
 
 $observeEnqueueSpliceRecord = EnqueueSpliceRecord;
 $observeBeginPerformSplice = BeginPerformSplice;
 $observeEndPerformSplice = EndPerformSplice;
 
-utils.ExportToRuntime(function(to) {
-  to["native_object_get_notifier"] = NativeObjectGetNotifier;
-  to["native_object_notifier_perform_change"] =
-      NativeObjectNotifierPerformChange;
-  to["native_object_observe"] = NativeObjectObserve;
-  to["observers_begin_perform_splice"] = BeginPerformSplice;
-  to["observers_end_perform_splice"] = EndPerformSplice;
-  to["observers_enqueue_splice"] = EnqueueSpliceRecord;
-  to["observers_notify_change"] = NotifyChange;
-});
+%InstallToContext([
+  "native_object_get_notifier", NativeObjectGetNotifier,
+  "native_object_notifier_perform_change", NativeObjectNotifierPerformChange,
+  "native_object_observe", NativeObjectObserve,
+  "observers_begin_perform_splice", BeginPerformSplice,
+  "observers_end_perform_splice", EndPerformSplice,
+  "observers_enqueue_splice", EnqueueSpliceRecord,
+  "observers_notify_change", NotifyChange,
+]);
 
 })