ES6: Implement WeakMap and WeakSet constructor logic

src/collection.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.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 var $Set = global.Set;
 var $Map = global.Map;
 
 
-// TODO(arv): Move these general functions to v8natives.js when Map and Set are
-// no longer experimental.
-
-
-// 7.4.1 CheckIterable ( obj )
-function ToIterable(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    return UNDEFINED;
-  }
-  return obj[symbolIterator];
-}
-
-
-// 7.4.2 GetIterator ( obj, method )
-function GetIterator(obj, method) {
-  if (IS_UNDEFINED(method)) {
-    method = ToIterable(obj);
-  }
-  if (!IS_SPEC_FUNCTION(method)) {
-    throw MakeTypeError('not_iterable', [obj]);
-  }
-  var iterator = %_CallFunction(obj, method);
-  if (!IS_SPEC_OBJECT(iterator)) {
-    throw MakeTypeError('not_an_iterator', [iterator]);
-  }
-  return iterator;
-}
-
-
 // -------------------------------------------------------------------
 // Harmony Set
 
 function SetConstructor(iterable) {
   if (!%_IsConstructCall()) {
     throw MakeTypeError('constructor_not_function', ['Set']);
   }
 
   var iter, adder;
 
@@ skipping 238 matching lines @@
     "get", MapGetJS,
     "set", MapSetJS,
     "has", MapHasJS,
     "delete", MapDeleteJS,
     "clear", MapClearJS,
     "forEach", MapForEach
   ));
 }
 
 SetUpMap();