[builtins] move String.prototype[@@iterator] to C++ builtin

src/js/string-iterator.js

Index: src/js/string-iterator.js
diff --git a/src/js/string-iterator.js b/src/js/string-iterator.js
deleted file mode 100644
index 2319e5a67950714c06a28c21edb67a45d9fbe3b1..0000000000000000000000000000000000000000
--- a/src/js/string-iterator.js
+++ /dev/null
@@ -1,98 +0,0 @@
-// 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.
-
-(function(global, utils) {
-
-"use strict";
-
-%CheckIsBootstrapping();
-
-// -------------------------------------------------------------------
-// Imports
-
-var GlobalString = global.String;
-var IteratorPrototype = utils.ImportNow("IteratorPrototype");
-var iteratorSymbol = utils.ImportNow("iterator_symbol");
-var stringIteratorIteratedStringSymbol =
-    utils.ImportNow("string_iterator_iterated_string_symbol");
-var stringIteratorNextIndexSymbol =
-    utils.ImportNow("string_iterator_next_index_symbol");
-var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
-
-// -------------------------------------------------------------------
-
-function StringIterator() {}
-
-
-// 21.1.5.1 CreateStringIterator Abstract Operation
-function CreateStringIterator(string) {
-  CHECK_OBJECT_COERCIBLE(string, 'String.prototype[Symbol.iterator]');
-  var s = TO_STRING(string);
-  var iterator = new StringIterator;
-  SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol, s);
-  SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, 0);
-  return iterator;
-}
-
-
-// ES6 section 21.1.5.2.1 %StringIteratorPrototype%.next ( )
-function StringIteratorNext() {
-  var iterator = this;
-  var value = UNDEFINED;
-  var done = true;
-
-  if (!IS_RECEIVER(iterator) ||
-      !HAS_DEFINED_PRIVATE(iterator, stringIteratorNextIndexSymbol)) {
-    throw %make_type_error(kIncompatibleMethodReceiver,
-                        'String Iterator.prototype.next');
-  }
-
-  var s = GET_PRIVATE(iterator, stringIteratorIteratedStringSymbol);
-  if (!IS_UNDEFINED(s)) {
-    var position = GET_PRIVATE(iterator, stringIteratorNextIndexSymbol);
-    var length = TO_UINT32(s.length);
-    if (position >= length) {
-      SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol, UNDEFINED);
-    } else {
-      var first = %_StringCharCodeAt(s, position);
-      value = %_StringCharFromCode(first);
-      done = false;
-      position++;
-
-      if (first >= 0xD800 && first <= 0xDBFF && position < length) {
-        var second = %_StringCharCodeAt(s, position);
-        if (second >= 0xDC00 && second <= 0xDFFF) {
-          value += %_StringCharFromCode(second);
-          position++;
-        }
-      }
-
-      SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, position);
-    }
-  }
-  return %_CreateIterResultObject(value, done);
-}
-
-
-// 21.1.3.27 String.prototype [ @@iterator ]( )
-function StringPrototypeIterator() {
-  return CreateStringIterator(this);
-}
-
-//-------------------------------------------------------------------
-
-%FunctionSetPrototype(StringIterator, {__proto__: IteratorPrototype});
-%FunctionSetInstanceClassName(StringIterator, 'String Iterator');
-
-utils.InstallFunctions(StringIterator.prototype, DONT_ENUM, [
-  'next', StringIteratorNext
-]);
-%AddNamedProperty(StringIterator.prototype, toStringTagSymbol,
-                  "String Iterator", READ_ONLY | DONT_ENUM);
-
-utils.SetFunctionName(StringPrototypeIterator, iteratorSymbol);
-%AddNamedProperty(GlobalString.prototype, iteratorSymbol,
-                  StringPrototypeIterator, DONT_ENUM);
-
-})