[builtins] Move StringIndexOf to a C++ builtin.

src/js/i18n.js

 // Copyright 2013 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.
 
 // ECMAScript 402 API implementation.
 
 /**
  * Intl object is a single object that has some named properties,
  * all of which are constructors.
  */
@@ skipping 15 matching lines @@
 var InstallFunctions = utils.InstallFunctions;
 var InstallGetter = utils.InstallGetter;
 var InternalArray = utils.InternalArray;
 var InternalRegExpMatch;
 var InternalRegExpReplace
 var ObjectHasOwnProperty = utils.ImportNow("ObjectHasOwnProperty");
 var OverrideFunction = utils.OverrideFunction;
 var patternSymbol = utils.ImportNow("intl_pattern_symbol");
 var resolvedSymbol = utils.ImportNow("intl_resolved_symbol");
 var SetFunctionName = utils.SetFunctionName;
-var StringIndexOf;
 var StringSubstr;
 var StringSubstring;
 
 utils.Import(function(from) {
   ArrayJoin = from.ArrayJoin;
   ArrayPush = from.ArrayPush;
   InternalRegExpMatch = from.InternalRegExpMatch;
   InternalRegExpReplace = from.InternalRegExpReplace;
-  StringIndexOf = from.StringIndexOf;
   StringSubstr = from.StringSubstr;
   StringSubstring = from.StringSubstring;
 });
 
 // Utilities for definitions
 
 function InstallFunction(object, name, func) {
   InstallFunctions(object, DONT_ENUM, [name, func]);
 }
 
@@ skipping 766 matching lines @@
  *
  * Returns false if the language tag is invalid.
  */
 function isStructuallyValidLanguageTag(locale) {
   // Check if it's well-formed, including grandfadered tags.
   if (IS_NULL(InternalRegExpMatch(GetLanguageTagRE(), locale))) {
     return false;
   }
 
   // Just return if it's a x- form. It's all private.
-  if (%_Call(StringIndexOf, locale, 'x-') === 0) {
+  if (%StringIndexOf(locale, 'x-', 0) === 0) {
     return true;
   }
 
   // Check if there are any duplicate variants or singletons (extensions).
 
   // Remove private use section.
   locale = %StringSplit(locale, '-x-', kMaxUint32)[0];
 
   // Skip language since it can match variant regex, so we start from 1.
   // We are matching i-klingon here, but that's ok, since i-klingon-klingon
@@ skipping 1210 matching lines @@
   if (IS_UNDEFINED(locales)) {
     language = GetDefaultICULocaleJS();
   } else if (IS_STRING(locales)) {
     language = canonicalizeLanguageTag(locales);
   } else {
     var locales = initializeLocaleList(locales);
     language = locales.length > 0 ? locales[0] : GetDefaultICULocaleJS();
   }
 
   // StringSplit is slower than this.
-  var pos = %_Call(StringIndexOf, language, '-');
+  var pos = %StringIndexOf(language, '-', 0);
   if (pos != -1) {
     language = %_Call(StringSubstring, language, 0, pos);
   }
 
   var CUSTOM_CASE_LANGUAGES = ['az', 'el', 'lt', 'tr'];
   var langIndex = %ArrayIndexOf(CUSTOM_CASE_LANGUAGES, language, 0);
   if (langIndex == -1) {
     // language-independent case conversion.
     return isToUpper ? %StringToUpperCaseI18N(s) : %StringToLowerCaseI18N(s);
   }
@@ skipping 198 matching lines @@
   }
 );
 
 %FunctionRemovePrototype(FormatDateToParts);
 
 utils.Export(function(to) {
   to.FormatDateToParts = FormatDateToParts;
 });
 
 })