[builtins] Migrate Object.keys to CodeStubAssembler builtin.

src/runtime/runtime-object.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 121 matching lines @@
                                           Handle<Object> key,
                                           LanguageMode language_mode) {
   bool success = false;
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, receiver, key, &success, LookupIterator::OWN);
   if (!success) return Nothing<bool>();
 
   return JSReceiver::DeleteProperty(&it, language_mode);
 }
 
+// ES #sec-object.keys
+RUNTIME_FUNCTION(Runtime_ObjectKeys) {
+  HandleScope scope(isolate);
+  Handle<Object> object = args.at(0);
+
+  // Convert the {object} to a proper {receiver}.
+  Handle<JSReceiver> receiver;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, receiver,
+                                     Object::ToObject(isolate, object));
+
+  // Collect the own keys for the {receiver}.
+  Handle<FixedArray> keys;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, keys,
+      KeyAccumulator::GetKeys(receiver, KeyCollectionMode::kOwnOnly,
+                              ENUMERABLE_STRINGS,
+                              GetKeysConversion::kConvertToString));
+  return *keys;
+}
+
 // ES6 19.1.3.2
 RUNTIME_FUNCTION(Runtime_ObjectHasOwnProperty) {
   HandleScope scope(isolate);
   Handle<Object> property = args.at(1);
 
   Handle<Name> key;
   uint32_t index;
   bool key_is_array_index = property->ToArrayIndex(&index);
 
   if (!key_is_array_index) {
@@ skipping 885 matching lines @@
   // While iteration alone may not have observable side-effects, calling
   // toNumber on an object will. Make sure the arg is not an array of objects.
   ElementsKind kind = JSObject::cast(*obj)->GetElementsKind();
   if (!IsFastNumberElementsKind(kind)) return isolate->heap()->ToBoolean(false);
 
   return isolate->heap()->ToBoolean(!obj->IterationHasObservableEffects());
 }
 
 }  // namespace internal
 }  // namespace v8