[api] Add PropertyDescriptor and DefineProperty().

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 65964d753baefb57e3c33f56e23522dee9216bd8..3b50cab8ece4cffb8ca5a6d3304da2dc0ea12e78 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -3691,6 +3691,57 @@ Maybe<bool> v8::Object::DefineOwnProperty(v8::Local<v8::Context> context,
   return success;
 }
 
+Maybe<bool> v8::Object::DefineProperty(v8::Local<v8::Context> context,
+                                       v8::Local<Name> key,
+                                       const PropertyDescriptor* descriptor) {
+  PREPARE_FOR_EXECUTION_PRIMITIVE(context, Object, DefineProperty, bool);
+  auto self = Utils::OpenHandle(this);
+  auto key_obj = Utils::OpenHandle(*key);
+
+  if (self->IsAccessCheckNeeded() &&

[Toon Verwaest, 2016/08/18 07:25:39]

I'm pretty sure that access is properly checked in DefineOwnProperty. I don't
think we need it above either.

[Franzi, 2016/08/18 09:56:24]

You're right. Deleted in in v8::Object::DefineOwnProperty() as well. 

+      !isolate->MayAccess(handle(isolate->context()),
+                          i::Handle<i::JSObject>::cast(self))) {
+    isolate->ReportFailedAccessCheck(i::Handle<i::JSObject>::cast(self));
+    return Nothing<bool>();
+  }
+
+  i::PropertyDescriptor desc;
+  if (descriptor->has_value()) {
+    if (descriptor->value().IsEmpty()) {
+      desc.set_value(isolate->factory()->undefined_value());
+    } else {
+      desc.set_value(Utils::OpenHandle(*descriptor->value()));
+    }
+  }
+  if (descriptor->has_get()) {
+    if (descriptor->get().IsEmpty()) {
+      desc.set_get(isolate->factory()->undefined_value());
+    } else {
+      desc.set_get(Utils::OpenHandle(*descriptor->get()));
+    }
+  }
+  if (descriptor->has_set()) {
+    if (descriptor->set().IsEmpty()) {
+      desc.set_set(isolate->factory()->undefined_value());
+    } else {
+      desc.set_set(Utils::OpenHandle(*descriptor->set()));
+    }
+  }
+  if (descriptor->has_enumerable()) {
+    desc.set_enumerable(descriptor->enumerable());
+  }
+  if (descriptor->has_configurable()) {
+    desc.set_configurable(descriptor->configurable());
+  }
+  if (descriptor->has_writable()) {
+    desc.set_writable(descriptor->writable());
+  }
+
+  auto success = i::JSReceiver::DefineOwnProperty(isolate, self, key_obj, &desc,
+                                                  i::Object::DONT_THROW);
+  RETURN_ON_FAILED_EXECUTION_PRIMITIVE(bool);
+  return success;
+}
 
 MUST_USE_RESULT
 static i::MaybeHandle<i::Object> DefineObjectProperty(