[es6] Partially implement Reflect.preventExtensions.

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 683 matching lines @@
   // %ThrowTypeError% must not have a name property.
   JSReceiver::DeleteProperty(function, factory()->name_string()).Assert();
 
   // length needs to be non configurable.
   Handle<Object> value(Smi::FromInt(function->shared()->length()), isolate());
   JSObject::SetOwnPropertyIgnoreAttributes(
       function, factory()->length_string(), value,
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY))
       .Assert();
 
-  JSObject::PreventExtensions(function).Assert();
+  if (JSObject::PreventExtensions(function, THROW_ON_ERROR).IsNothing())
+    DCHECK(false);
 
   return function;
 }
 
 
 // ECMAScript 5th Edition, 13.2.3
 Handle<JSFunction> Genesis::GetRestrictedFunctionPropertiesThrower() {
   if (restricted_function_properties_thrower_.is_null()) {
     restricted_function_properties_thrower_ = GetThrowTypeErrorIntrinsic(
         Builtins::kRestrictedFunctionPropertiesThrower);
@@ skipping 1475 matching lines @@
   JSObject::AddProperty(global, reflect_string, reflect, DONT_ENUM);
 
   SimpleInstallFunction(reflect, "deleteProperty",
                         Builtins::kReflectDeleteProperty, 2, true);
   SimpleInstallFunction(reflect, "get",
                         Builtins::kReflectGet, 3, false);
   SimpleInstallFunction(reflect, "has",
                         Builtins::kReflectHas, 2, true);
   SimpleInstallFunction(reflect, "isExtensible",
                         Builtins::kReflectIsExtensible, 1, true);
+  SimpleInstallFunction(reflect, "preventExtensions",
+                        Builtins::kReflectPreventExtensions, 1, true);
 }
 
 
 void Genesis::InitializeGlobal_harmony_sharedarraybuffer() {
   if (!FLAG_harmony_sharedarraybuffer) return;
 
   Handle<JSGlobalObject> global(
       JSGlobalObject::cast(native_context()->global_object()));
 
   Handle<JSFunction> shared_array_buffer_fun = InstallFunction(
@@ skipping 1105 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8