[es6] Iterators and generators should "extend" %IteratorPrototype%

src/generator.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.
 
 (function(global, shared, exports) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 48 matching lines @@
   } else if (continuation == 0) {
     // Generator is already closed.
     throw exn;
   } else {
     // Generator is running.
     throw MakeTypeError(kGeneratorRunning);
   }
 }
 
 
-function GeneratorObjectIterator() {
-  return this;
-}
-
-
 function GeneratorFunctionConstructor(arg1) {  // length == 1
   var source = $newFunctionString(arguments, 'function*');
   var global_proxy = %GlobalProxy(GeneratorFunctionConstructor);
   // Compile the string in the constructor and not a helper so that errors
   // appear to come from here.
   var f = %_CallFunction(global_proxy, %CompileString(source, true));
   %FunctionMarkNameShouldPrintAsAnonymous(f);
   return f;
 }
 
 // ----------------------------------------------------------------------------
 
 // Both Runtime_GeneratorNext and Runtime_GeneratorThrow are supported by
 // neither Crankshaft nor TurboFan, disable optimization of wrappers here.
 %NeverOptimizeFunction(GeneratorObjectNext);
 %NeverOptimizeFunction(GeneratorObjectThrow);
 
 // Set up non-enumerable functions on the generator prototype object.
 var GeneratorObjectPrototype = GeneratorFunctionPrototype.prototype;
 $installFunctions(GeneratorObjectPrototype,
                  DONT_ENUM,
                  ["next", GeneratorObjectNext,
                   "throw", GeneratorObjectThrow]);
 
-$setFunctionName(GeneratorObjectIterator, symbolIterator);
-%AddNamedProperty(GeneratorObjectPrototype, symbolIterator,
-    GeneratorObjectIterator, DONT_ENUM | DONT_DELETE | READ_ONLY);
 %AddNamedProperty(GeneratorObjectPrototype, "constructor",
     GeneratorFunctionPrototype, DONT_ENUM | READ_ONLY);
 %AddNamedProperty(GeneratorObjectPrototype,
     symbolToStringTag, "Generator", DONT_ENUM | READ_ONLY);
 %InternalSetPrototype(GeneratorFunctionPrototype, GlobalFunction.prototype);
 %AddNamedProperty(GeneratorFunctionPrototype,
     symbolToStringTag, "GeneratorFunction", DONT_ENUM | READ_ONLY);
 %AddNamedProperty(GeneratorFunctionPrototype, "constructor",
     GeneratorFunction, DONT_ENUM | READ_ONLY);
 %InternalSetPrototype(GeneratorFunction, GlobalFunction);
 %SetCode(GeneratorFunction, GeneratorFunctionConstructor);
 
 })