[proxies] Fix HasProperty and getOwnPropertySymbols

src/key-accumulator.cc

 // Copyright 2013 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/key-accumulator.h"
 
 #include "src/elements.h"
 #include "src/factory.h"
 #include "src/isolate-inl.h"
 #include "src/objects-inl.h"
@@ skipping 213 matching lines @@
 MaybeHandle<FixedArray> FilterProxyKeys(Isolate* isolate, Handle<JSProxy> owner,
                                         Handle<FixedArray> keys,
                                         PropertyFilter filter) {
   if (filter == ALL_PROPERTIES) {
     // Nothing to do.
     return keys;
   }
   int store_position = 0;
   for (int i = 0; i < keys->length(); ++i) {
     Handle<Name> key(Name::cast(keys->get(i)), isolate);
-    if (key->IsSymbol()) {
-      if ((filter & SKIP_SYMBOLS) || Handle<Symbol>::cast(key)->is_private()) {
-        continue;  // Skip this key.
-      }
-    }
-    if (filter & SKIP_STRINGS) continue;  // Skip this key.
+    if (key->FilterKey(filter)) continue;  // Skip this key.
     if (filter & ONLY_ENUMERABLE) {
       PropertyDescriptor desc;
       bool found =
           JSProxy::GetOwnPropertyDescriptor(isolate, owner, key, &desc);
       if (isolate->has_pending_exception()) return MaybeHandle<FixedArray>();
       if (!found || !desc.enumerable()) continue;  // Skip this key.
     }
     // Keep this key.
     if (store_position != i) {
       keys->set(store_position, *key);
@@ skipping 60 matching lines @@
     level_lengths_.push_back(level_symbol_length_);
   }
   elements_.push_back(new std::vector<uint32_t>());
   level_string_length_ = 0;
   level_symbol_length_ = 0;
 }
 
 
 }  // namespace internal
 }  // namespace v8