[proxies] allow duplicate keys for [[OwnPropertyKeys]] trap.

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 11 matching lines @@
 }
 
 
 Handle<FixedArray> KeyAccumulator::GetKeys(GetKeysConversion convert) {
   if (length_ == 0) {
     return isolate_->factory()->empty_fixed_array();
   }
   // Make sure we have all the lengths collected.
   NextPrototype();
 
+  if (type_ == OWN_ONLY && !ownProxyKeys_.is_null()) {
+    return ownProxyKeys_;
+  }
   // Assemble the result array by first adding the element keys and then the
   // property keys. We use the total number of String + Symbol keys per level in
   // |level_lengths_| and the available element keys in the corresponding bucket
   // in |elements_| to deduce the number of keys to take from the
   // |string_properties_| and |symbol_properties_| set.
   Handle<FixedArray> result = isolate_->factory()->NewFixedArray(length_);
   int insertion_index = 0;
   int string_properties_index = 0;
   int symbol_properties_index = 0;
   // String and Symbol lengths always come in pairs:
@@ skipping 211 matching lines @@
 
 // Returns "nothing" in case of exception, "true" on success.
 Maybe<bool> KeyAccumulator::AddKeysFromProxy(Handle<JSProxy> proxy,
                                              Handle<FixedArray> keys) {
   ASSIGN_RETURN_ON_EXCEPTION_VALUE(
       isolate_, keys, FilterProxyKeys(isolate_, proxy, keys, filter_),
       Nothing<bool>());
   // Proxies define a complete list of keys with no distinction of
   // elements and properties, which breaks the normal assumption for the
   // KeyAccumulator.
-  AddKeys(keys, PROXY_MAGIC);
+  if (type_ == OWN_ONLY) {
+    ownProxyKeys_ = keys;
+    level_string_length_ = keys->length();
+    length_ = level_string_length_;
+  } else {
+    AddKeys(keys, PROXY_MAGIC);
+  }
   // Invert the current length to indicate a present proxy, so we can ignore
   // element keys for this level. Otherwise we would not fully respect the order
   // given by the proxy.
   level_string_length_ = -level_string_length_;
   return Just(true);
 }
 
 
 void KeyAccumulator::AddElementKeysFromInterceptor(
     Handle<JSObject> array_like) {
@@ skipping 32 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