Revert of Rename String.prototype.contains to 'includes'.

src/harmony-string.js

 // 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.
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $String = global.String;
 // var $Array = global.Array;
@@ skipping 77 matching lines @@
   var start = end - ss_len;
   if (start < 0) {
     return false;
   }
 
   return %StringLastIndexOf(s, ss, start) === start;
 }
 
 
 // ES6 draft 04-05-14, section 21.1.3.6
-function StringIncludes(searchString /* position */) {  // length == 1
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.includes");
+function StringContains(searchString /* position */) {  // length == 1
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.contains");
 
   var s = TO_STRING_INLINE(this);
 
   if (IS_REGEXP(searchString)) {
     throw MakeTypeError("first_argument_not_regexp",
-                        ["String.prototype.includes"]);
+                        ["String.prototype.contains"]);
   }
 
   var ss = TO_STRING_INLINE(searchString);
   var pos = 0;
   if (%_ArgumentsLength() > 1) {
     pos = %_Arguments(1);  // position
     pos = ToInteger(pos);
   }
 
   var s_len = s.length;
@@ skipping 61 matching lines @@
   %CheckIsBootstrapping();
 
   // Set up the non-enumerable functions on the String object.
   InstallFunctions($String, DONT_ENUM, $Array(
     "fromCodePoint", StringFromCodePoint
   ));
 
   // Set up the non-enumerable functions on the String prototype object.
   InstallFunctions($String.prototype, DONT_ENUM, $Array(
     "codePointAt", StringCodePointAt,
-    "includes", StringIncludes,
+    "contains", StringContains,
     "endsWith", StringEndsWith,
     "repeat", StringRepeat,
     "startsWith", StringStartsWith
   ));
 }
 
 ExtendStringPrototype();