Merged: [runtime] Mark old JSGlobalProxy's map as unstable when an iframe navigates away.

test/mjsunit/regress/regress-crbug-683667.js

Index: test/mjsunit/regress/regress-crbug-683667.js
diff --git a/test/mjsunit/regress/regress-crbug-683667.js b/test/mjsunit/regress/regress-crbug-683667.js
new file mode 100644
index 0000000000000000000000000000000000000000..adba522129778f4f1437d2c3ef99f579d7e171a8
--- /dev/null
+++ b/test/mjsunit/regress/regress-crbug-683667.js
@@ -0,0 +1,14 @@
+// Copyright 2017 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.
+
+// Flags: --expose-gc --verify-heap
+
+var realm = Realm.create();
+var g = Realm.global(realm);
+var obj = {x: 0, g: g};
+
+// Navigation will replace JSGlobalObject behind the JSGlobalProxy g and
+// therefore will change the g's map. The old map must be marked as non-stable.
+Realm.navigate(realm);
+gc();