[d8] bounds-check before getting Shell::Worker internal field

test/mjsunit/regress/regress-4271.js

Index: test/mjsunit/regress/regress-4271.js
diff --git a/test/mjsunit/regress/regress-4271.js b/test/mjsunit/regress/regress-4271.js
new file mode 100644
index 0000000000000000000000000000000000000000..eff0803a0974977a7af4a6273dd0d6aaa8ea204c
--- /dev/null
+++ b/test/mjsunit/regress/regress-4271.js
@@ -0,0 +1,24 @@
+// Copyright 2015 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.
+
+// Throw rather than overflow internal field index
+
+assertThrows(function() {
+  Worker.prototype.terminate();
+});
+
+assertThrows(function() {
+  Worker.prototype.getMessage();
+});
+
+assertThrows(function() {
+  Worker.prototype.postMessage({});
+});
+
+// Don't throw for real worker
+
+var worker = new Worker('');
+worker.getMessage();
+worker.postMessage({});
+worker.terminate();