Implement String.prototype.codePointAt and String.fromCodePoint.

test/mjsunit/harmony/string-codepointat.js

Index: test/mjsunit/harmony/string-codepointat.js
diff --git a/test/mjsunit/harmony/string-codepointat.js b/test/mjsunit/harmony/string-codepointat.js
new file mode 100644
index 0000000000000000000000000000000000000000..411b0f23c7e109fad96520ee84ca066d00f5f308
--- /dev/null
+++ b/test/mjsunit/harmony/string-codepointat.js
@@ -0,0 +1,91 @@
+// Copyright 2014 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-strings
+
+// Tests taken from:
+// https://github.com/mathiasbynens/String.prototype.codePointAt
+
+assertEquals(String.prototype.codePointAt.length, 1);
+assertEquals(String.prototype.propertyIsEnumerable("codePointAt"), false);
+
+// String that starts with a BMP symbol
+assertEquals("abc\uD834\uDF06def".codePointAt(""), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt("_"), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(-Infinity), undefined);
+assertEquals("abc\uD834\uDF06def".codePointAt(-1), undefined);
+assertEquals("abc\uD834\uDF06def".codePointAt(-0), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(0), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(3), 0x1D306);
+assertEquals("abc\uD834\uDF06def".codePointAt(4), 0xDF06);
+assertEquals("abc\uD834\uDF06def".codePointAt(5), 0x64);
+assertEquals("abc\uD834\uDF06def".codePointAt(42), undefined);
+assertEquals("abc\uD834\uDF06def".codePointAt(Infinity), undefined);
+assertEquals("abc\uD834\uDF06def".codePointAt(Infinity), undefined);
+assertEquals("abc\uD834\uDF06def".codePointAt(NaN), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(false), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(null), 0x61);
+assertEquals("abc\uD834\uDF06def".codePointAt(undefined), 0x61);
+
+// String that starts with an astral symbol
+assertEquals("\uD834\uDF06def".codePointAt(""), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt("1"), 0xDF06);
+assertEquals("\uD834\uDF06def".codePointAt("_"), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(-1), undefined);
+assertEquals("\uD834\uDF06def".codePointAt(-0), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(0), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(1), 0xDF06);
+assertEquals("\uD834\uDF06def".codePointAt(42), undefined);
+assertEquals("\uD834\uDF06def".codePointAt(false), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(null), 0x1D306);
+assertEquals("\uD834\uDF06def".codePointAt(undefined), 0x1D306);
+
+// Lone high surrogates
+assertEquals("\uD834abc".codePointAt(""), 0xD834);
+assertEquals("\uD834abc".codePointAt("_"), 0xD834);
+assertEquals("\uD834abc".codePointAt(), 0xD834);
+assertEquals("\uD834abc".codePointAt(-1), undefined);
+assertEquals("\uD834abc".codePointAt(-0), 0xD834);
+assertEquals("\uD834abc".codePointAt(0), 0xD834);
+assertEquals("\uD834abc".codePointAt(false), 0xD834);
+assertEquals("\uD834abc".codePointAt(NaN), 0xD834);
+assertEquals("\uD834abc".codePointAt(null), 0xD834);
+assertEquals("\uD834abc".codePointAt(undefined), 0xD834);
+
+// Lone low surrogates
+assertEquals("\uDF06abc".codePointAt(""), 0xDF06);
+assertEquals("\uDF06abc".codePointAt("_"), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(-1), undefined);
+assertEquals("\uDF06abc".codePointAt(-0), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(0), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(false), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(NaN), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(null), 0xDF06);
+assertEquals("\uDF06abc".codePointAt(undefined), 0xDF06);
+
+assertThrows(function() {
+  String.prototype.codePointAt.call(undefined);
+}, TypeError);
+assertThrows(function() {
+  String.prototype.codePointAt.call(undefined, 4);
+}, TypeError);
+assertThrows(function() {
+  String.prototype.codePointAt.call(null);
+}, TypeError);
+assertThrows(function() {
+  String.prototype.codePointAt.call(null, 4);
+}, TypeError);
+assertEquals(String.prototype.codePointAt.call(42, 0), 0x34);
+assertEquals(String.prototype.codePointAt.call(42, 1), 0x32);
+assertEquals(String.prototype.codePointAt.call({
+  toString: function() { return "abc"; }
+}, 2), 0x63);
+var tmp = 0;
+assertEquals(String.prototype.codePointAt.call({
+  toString: function() { ++tmp; return String(tmp); }
+}, 0), 0x31);
+assertEquals(tmp, 1);