Make all global private symbols own symbols.

src/array-iterator.js

Index: src/array-iterator.js
diff --git a/src/array-iterator.js b/src/array-iterator.js
index f04d6c974a4d41ea27347afde466ec1166e38d31..796ee064eb918865259a2d9a77b49c378b7a048c 100644
--- a/src/array-iterator.js
+++ b/src/array-iterator.js
@@ -10,9 +10,11 @@
 // var $Array = global.Array;
 
 
-var arrayIteratorObjectSymbol = GLOBAL_PRIVATE("ArrayIterator#object");
-var arrayIteratorNextIndexSymbol = GLOBAL_PRIVATE("ArrayIterator#next");
-var arrayIterationKindSymbol = GLOBAL_PRIVATE("ArrayIterator#kind");
+var arrayIteratorObjectSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#object");
+var arrayIteratorNextIndexSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#next");
+var arrayIterationKindSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#kind");
+
+var arrayEndOfIterationMarker = new $Object();
 
 
 function ArrayIterator() {}
@@ -50,13 +52,13 @@ function ArrayIteratorIterator() {
 function ArrayIteratorNext() {
   var iterator = ToObject(this);
 
-  if (!HAS_PRIVATE(iterator, arrayIteratorObjectSymbol)) {
+  if (!HAS_DEFINED_PRIVATE(iterator, arrayIteratorObjectSymbol)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Array Iterator.prototype.next']);
   }
 
   var array = GET_PRIVATE(iterator, arrayIteratorObjectSymbol);
-  if (IS_UNDEFINED(array)) {
+  if (array === arrayEndOfIterationMarker) {
     return CreateIteratorResultObject(UNDEFINED, true);
   }
 
@@ -67,7 +69,7 @@ function ArrayIteratorNext() {
   // "sparse" is never used.
 
   if (index >= length) {
-    SET_PRIVATE(iterator, arrayIteratorObjectSymbol, UNDEFINED);
+    SET_PRIVATE(iterator, arrayIteratorObjectSymbol, arrayEndOfIterationMarker);
     return CreateIteratorResultObject(UNDEFINED, true);
   }