Revert of [builtins] Migrate String.prototype.charCodeAt and String.prototype.charAt to TurboFan.

src/js/string.js

 // Copyright 2012 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) {
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
@@ skipping 39 matching lines @@
 
 // ECMA-262 section 15.5.4.3
 function StringValueOf() {
   if (!IS_STRING(this) && !IS_STRING_WRAPPER(this)) {
     throw MakeTypeError(kNotGeneric, 'String.prototype.valueOf');
   }
   return %_ValueOf(this);
 }
 
 
+// ECMA-262, section 15.5.4.4
+function StringCharAtJS(pos) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.charAt");
+
+  var result = %_StringCharAt(this, pos);
+  if (%_IsSmi(result)) {
+    result = %_StringCharAt(TO_STRING(this), TO_INTEGER(pos));
+  }
+  return result;
+}
+
+
+// ECMA-262 section 15.5.4.5
+function StringCharCodeAtJS(pos) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.charCodeAt");
+
+  var result = %_StringCharCodeAt(this, pos);
+  if (!%_IsSmi(result)) {
+    result = %_StringCharCodeAt(TO_STRING(this), TO_INTEGER(pos));
+  }
+  return result;
+}
+
+
 // ECMA-262, section 15.5.4.6
 function StringConcat(other /* and more */) {  // length == 1
   "use strict";
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.concat");
   var s = TO_STRING(this);
   var len = arguments.length;
   for (var i = 0; i < len; ++i) {
     s = s + TO_STRING(arguments[i]);
   }
   return s;
@@ skipping 756 matching lines @@
       result += TO_STRING(arguments[i]);
     }
     result += TO_STRING(raw[i]);
   }
 
   return result;
 }
 
 // -------------------------------------------------------------------
 
+// Set the String function and constructor.
+%FunctionSetPrototype(GlobalString, new GlobalString());
+
+// Set up the constructor property on the String prototype object.
+%AddNamedProperty(
+    GlobalString.prototype, "constructor", GlobalString, DONT_ENUM);
+
 // Set up the non-enumerable functions on the String object.
 utils.InstallFunctions(GlobalString, DONT_ENUM, [
   "fromCharCode", StringFromCharCode,
   "fromCodePoint", StringFromCodePoint,
   "raw", StringRaw
 ]);
 
 // Set up the non-enumerable functions on the String prototype object.
 utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "valueOf", StringValueOf,
   "toString", StringToString,
+  "charAt", StringCharAtJS,
+  "charCodeAt", StringCharCodeAtJS,
   "codePointAt", StringCodePointAt,
   "concat", StringConcat,
   "endsWith", StringEndsWith,
   "includes", StringIncludes,
   "indexOf", StringIndexOf,
   "lastIndexOf", StringLastIndexOf,
   "localeCompare", StringLocaleCompareJS,
   "match", StringMatchJS,
   "normalize", StringNormalize,
   "repeat", StringRepeat,
@@ skipping 25 matching lines @@
   "strike", StringStrike,
   "sub", StringSub,
   "sup", StringSup
 ]);
 
 // -------------------------------------------------------------------
 // Exports
 
 utils.Export(function(to) {
   to.ExpandReplacement = ExpandReplacement;
+  to.StringCharAt = StringCharAtJS;
   to.StringIndexOf = StringIndexOf;
   to.StringLastIndexOf = StringLastIndexOf;
   to.StringMatch = StringMatchJS;
   to.StringReplace = StringReplace;
   to.StringSlice = StringSlice;
   to.StringSplit = StringSplitJS;
   to.StringSubstr = StringSubstr;
   to.StringSubstring = StringSubstring;
 });
 
 })