WIP context-allocation for “this” in arrow functions

test/mjsunit/harmony/arrow-functions-scoping.js

+// 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.
+
+// Flags: --harmony-arrow-functions
+
+// The following are tests from:
+// http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax
+
+// ''=>'' has only lexical ''this'', no dynamic ''this''
+var obj = {
+  method: function () {
+    return () => this;
+  }
+};
+assertSame(obj, obj.method()());
+
+var fake = {steal: obj.method()};
+assertSame(obj, fake.steal());
+
+// But ''function'' still has dynamic ''this'' of course
+var real = {borrow: obj.method};
+assertSame(real, real.borrow()());