[proxies] [[HasProperty]]: fix trap call.

test/mjsunit/harmony/proxies-has.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-proxies
+
+var target = {
+  "target_one": 1
+};
+target.__proto__ = {
+  "target_two": 2
+};
+var handler = {
+  has: function(target, name) {
+    return name == "present";
+  }
+}
+
+var proxy = new Proxy(target, handler);
+
+// Test simple cases.
+assertTrue("present" in proxy);
+assertFalse("nonpresent" in proxy);
+
+// Test interesting algorithm steps:
+
+// Step 7: Fall through to target if trap is undefined.
+handler.has = undefined;
+assertTrue("target_one" in proxy);
+assertTrue("target_two" in proxy);
+assertFalse("in_your_dreams" in proxy);
+
+// Step 8: Result is converted to boolean.
+var result = 1;
+handler.has = function(t, n) { return result; }
+assertTrue("foo" in proxy);
+result = {};
+assertTrue("foo" in proxy);
+result = undefined;
+assertFalse("foo" in proxy);
+result = "string";
+assertTrue("foo" in proxy);
+
+// Step 9b i. Trap result must confirm presence of non-configurable properties
+// of the target.
+Object.defineProperty(target, "nonconf", {value: 1, configurable: false});
+result = false;
+assertThrows("'nonconf' in proxy", TypeError);
+
+// Step 9b iii. Trap result must confirm presence of all own properties of
+// non-extensible targets.
+Object.freeze(target);
+assertThrows("'nonconf' in proxy", TypeError);
+assertThrows("'target_one' in proxy", TypeError);
+assertFalse("target_two" in proxy);
+assertFalse("in_your_dreams" in proxy);