[keys] keep track of first and last non-empty prototype

src/keys.h

Index: src/keys.h
diff --git a/src/keys.h b/src/keys.h
index 6b8f4b8162911de6053ae2c00f25152200987f06..e11b8a3622745dff3001447ecdfea5ee886e98aa 100644
--- a/src/keys.h
+++ b/src/keys.h
@@ -39,7 +39,9 @@ class KeyAccumulator final BASE_EMBEDDED {
   static MaybeHandle<FixedArray> GetKeys(
       Handle<JSReceiver> object, KeyCollectionMode mode, PropertyFilter filter,
       GetKeysConversion keys_conversion = GetKeysConversion::kKeepNumbers,
-      bool filter_proxy_keys = true, bool is_for_in = false);
+      bool filter_proxy_keys = true, bool is_for_in = false,
+      JSReceiver* first_non_empty_prototype = nullptr,
+      JSReceiver* last_non_empty_prototype = nullptr);
   Handle<FixedArray> GetKeys(
       GetKeysConversion convert = GetKeysConversion::kKeepNumbers);
   Maybe<bool> CollectKeys(Handle<JSReceiver> receiver,
@@ -64,6 +66,12 @@ class KeyAccumulator final BASE_EMBEDDED {
   void set_filter_proxy_keys(bool filter) { filter_proxy_keys_ = filter; }
   void set_is_for_in(bool value) { is_for_in_ = value; }
   void set_skip_indices(bool value) { skip_indices_ = value; }
+  void set_first_non_empty_prototype(JSReceiver* object) {
+    first_non_empty_prototype_ = handle(object, isolate_);
+  }
+  void set_last_non_empty_prototype(JSReceiver* object) {
+    last_non_empty_prototype_ = handle(object, isolate_);
+  }
 
  private:
   Maybe<bool> CollectOwnKeys(Handle<JSReceiver> receiver,
@@ -82,6 +90,8 @@ class KeyAccumulator final BASE_EMBEDDED {
   // keys_ is either an Handle<OrderedHashSet> or in the case of own JSProxy
   // keys a Handle<FixedArray>.
   Handle<FixedArray> keys_;
+  Handle<JSReceiver> first_non_empty_prototype_;
+  Handle<JSReceiver> last_non_empty_prototype_;
   KeyCollectionMode mode_;
   PropertyFilter filter_;
   bool filter_proxy_keys_ = true;
@@ -117,6 +127,8 @@ class FastKeyAccumulator {
 
   Isolate* isolate_;
   Handle<JSReceiver> receiver_;
+  Handle<JSReceiver> first_non_empty_prototype_;
+  Handle<JSReceiver> last_non_empty_prototype_;
   KeyCollectionMode mode_;
   PropertyFilter filter_;
   bool filter_proxy_keys_ = true;