DevTools: Show preview for ES6 MapIterator, SetIterator in console.

LayoutTests/inspector/console/console-dir-es6.html

Index: LayoutTests/inspector/console/console-dir-es6.html
diff --git a/LayoutTests/inspector/console/console-dir-es6.html b/LayoutTests/inspector/console/console-dir-es6.html
index 741bc3a7d5943fc5c4cb1d9863c23738d09170de..1544b7cf8875ffb0deae60af6f2c35ebae218c8e 100644
--- a/LayoutTests/inspector/console/console-dir-es6.html
+++ b/LayoutTests/inspector/console/console-dir-es6.html
@@ -36,6 +36,17 @@ function onload()
     // Test "No Entries" placeholder.
     console.dir(new WeakMap());
 
+    // Test Map/Set iterators.
+    var m = new Map();
+    m.set(obj, {foo: 1});
+    var s = new Set();
+    s.add(obj);
+    [m, s].forEach(function(c) {
+        console.dir(c.keys());
+        console.dir(c.values());
+        console.dir(c.entries());
+    });
+
     runTest();
 }