Don't use OwnPrototypeChainLength in GetOwnPropertyNames

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 8203b36a97f1dee7ef9c14a2cf413ae2c370c7e4..ea6e34d3916d80067c564bf47a6599083097a460 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2327,9 +2327,9 @@ class JSObject: public JSReceiver {
   // with the specified attributes (ignoring interceptors).
   int NumberOfOwnProperties(PropertyAttributes filter = NONE);
   // Fill in details for properties into storage starting at the specified
-  // index.
-  void GetOwnPropertyNames(
-      FixedArray* storage, int index, PropertyAttributes filter = NONE);
+  // index. Returns the number of properties that were added.
+  int GetOwnPropertyNames(FixedArray* storage, int index,
+                          PropertyAttributes filter = NONE);
 
   // Returns the number of properties on this object filtering out properties
   // with the specified attributes (ignoring interceptors).
@@ -3862,10 +3862,8 @@ class Dictionary: public HashTable<Derived, Shape, Key> {
                   PropertyAttributes filter,
                   SortMode sort_mode);
   // Fill in details for properties into storage.
-  void CopyKeysTo(FixedArray* storage,
-                  int index,
-                  PropertyAttributes filter,
-                  SortMode sort_mode);
+  int CopyKeysTo(FixedArray* storage, int index, PropertyAttributes filter,
+                 SortMode sort_mode);
 
   // Accessors for next enumeration index.
   void SetNextEnumerationIndex(int index) {