Expose internal properties of map/set iterators via mirrors.

test/mjsunit/es6/mirror-iterators.js

Index: test/mjsunit/es6/mirror-iterators.js
diff --git a/test/mjsunit/es6/mirror-iterators.js b/test/mjsunit/es6/mirror-iterators.js
index cc0b1e45f893139caa73238d48cf63e5463001ea..22ce42493f114cb7585b85a9a3b5a07ea476156b 100644
--- a/test/mjsunit/es6/mirror-iterators.js
+++ b/test/mjsunit/es6/mirror-iterators.js
@@ -23,6 +23,22 @@ function testIteratorMirror(iter, offset, expected, opt_limit) {
   assertArrayEquals(expected, values);
 }
 
+function testIteratorInternalProperties(iter, offset, kind, index, has_more) {
+  while (offset-- > 0) iter.next();
+
+  var mirror = debug.MakeMirror(iter);
+  assertTrue(mirror.isIterator());
+
+  var properties = mirror.internalProperties();
+  assertEquals(3, properties.length);
+  assertEquals("[[IteratorHasMore]]", properties[0].name());
+  assertEquals(has_more, properties[0].value().value());
+  assertEquals("[[IteratorIndex]]", properties[1].name());
+  assertEquals(index, properties[1].value().value());
+  assertEquals("[[IteratorKind]]", properties[2].name());
+  assertEquals(kind, properties[2].value().value());
+}
+
 var o1 = { foo: 1 };
 var o2 = { foo: 2 };
 
@@ -47,6 +63,11 @@ testIteratorMirror(map.keys(), 0, [41], 1);
 testIteratorMirror(map.values(), 0, [42], 1);
 testIteratorMirror(map.entries(), 0, [[41, 42]], 1);
 
+testIteratorInternalProperties(map.keys(), 0, "keys", 0, true);
+testIteratorInternalProperties(map.values(), 1, "values", 1, true);
+testIteratorInternalProperties(map.entries(), 2, "entries", 2, false);
+testIteratorInternalProperties(map.keys(), 3, "keys", 2, false);
+
 var set = new Set();
 set.add(41);
 set.add(42);
@@ -73,3 +94,10 @@ testIteratorMirror(set.entries(), 5, []);
 testIteratorMirror(set.keys(), 1, [42, o1], 2);
 testIteratorMirror(set.values(), 1, [42, o1], 2);
 testIteratorMirror(set.entries(), 1, [[42, 42], [o1, o1]], 2);
+
+testIteratorInternalProperties(set.keys(), 0, "values", 0, true);
+testIteratorInternalProperties(set.values(), 1, "values", 1, true);
+testIteratorInternalProperties(set.entries(), 2, "entries", 2, true);
+testIteratorInternalProperties(set.keys(), 3, "values", 3, true);
+testIteratorInternalProperties(set.values(), 4, "values", 4, false);
+testIteratorInternalProperties(set.entries(), 5, "entries", 4, false);