[runtime] [proxy] Fix Object.prototype.propertyIsEnumerable to support proxies

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 732 matching lines @@
   Maybe<bool> maybe = JSReceiver::HasProperty(receiver, name);
   if (!maybe.IsJust()) return isolate->heap()->exception();
   return isolate->heap()->ToBoolean(maybe.FromJust());
 }
 
 
 RUNTIME_FUNCTION(Runtime_IsPropertyEnumerable) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
 
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, object, 0);
   CONVERT_ARG_HANDLE_CHECKED(Name, key, 1);
 
   Maybe<PropertyAttributes> maybe =
       JSReceiver::GetOwnPropertyAttributes(object, key);
   if (!maybe.IsJust()) return isolate->heap()->exception();
-  if (maybe.FromJust() == ABSENT) maybe = Just(DONT_ENUM);
+  if (maybe.FromJust() == ABSENT) return isolate->heap()->false_value();
   return isolate->heap()->ToBoolean((maybe.FromJust() & DONT_ENUM) == 0);
 }
 
 
 // Returns either a FixedArray or, if the given object has an enum cache that
 // contains all enumerable properties of the object and its prototypes have
 // none, the map of the object. This is used to speed up the check for
 // deletions during a for-in.
 RUNTIME_FUNCTION(Runtime_GetPropertyNamesFast) {
   SealHandleScope shs(isolate);
@@ skipping 804 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_ObjectDefineProperties) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, o, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, properties, 1);
   return JSReceiver::DefineProperties(isolate, o, properties);
 }
 }  // namespace internal
 }  // namespace v8