[es6] Introduce %ToInteger and %ToLength.

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 312 matching lines @@
 }
 
 
 function ConvertAcceptListToTypeMap(arg) {
   // We use undefined as a sentinel for the default accept list.
   if (IS_UNDEFINED(arg))
     return arg;
 
   if (!IS_SPEC_OBJECT(arg)) throw MakeTypeError(kObserveInvalidAccept);
 
-  var len = $toInteger(arg.length);
+  var len = TO_INTEGER(arg.length);
   if (len < 0) len = 0;
 
   return TypeMapCreateFromList(arg, len);
 }
 
 
 // CallbackInfo's optimized state is just a number which represents its global
 // priority. When a change record must be enqueued for the callback, it
 // normalizes. When delivery clears any pending change records, it re-optimizes.
 function CallbackInfoGet(callback) {
@@ skipping 367 matching lines @@
   "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,
 ]);
 
 })