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

src/bootstrapper.cc

 // 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.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/code-stubs.h"
@@ skipping 2111 matching lines @@
     Handle<JSFunction> map_iterator_function = InstallFunction(
         builtins, "MapIterator", JS_MAP_ITERATOR_TYPE, JSMapIterator::kSize,
         isolate()->initial_object_prototype(), Builtins::kIllegal);
     native_context()->set_map_iterator_map(
         map_iterator_function->initial_map());
   }
 
   {
     // Create generator meta-objects and install them on the builtins object.
     Handle<JSObject> builtins(native_context()->builtins());
+    Handle<JSObject> iterator_prototype =
+        factory()->NewJSObject(isolate()->object_function(), TENURED);
     Handle<JSObject> generator_object_prototype =
         factory()->NewJSObject(isolate()->object_function(), TENURED);
     Handle<JSObject> generator_function_prototype =
         factory()->NewJSObject(isolate()->object_function(), TENURED);
+    SetObjectPrototype(generator_object_prototype, iterator_prototype);
+    JSObject::AddProperty(
+        builtins, factory()->InternalizeUtf8String("$iteratorPrototype"),
+        iterator_prototype,
+        static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY));
     JSObject::AddProperty(
         builtins,
         factory()->InternalizeUtf8String("GeneratorFunctionPrototype"),
         generator_function_prototype,
         static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY));
 
     JSObject::AddProperty(
         generator_function_prototype,
         factory()->InternalizeUtf8String("prototype"),
         generator_object_prototype,
@@ skipping 876 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 } }  // namespace v8::internal