[key-accumulator] Starting to reimplement the key-accumulator

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index bf0eaeda9e1914efb7ac255245cea0b698fd6cdd..cd5216d4fbdbdd28980f15be98cbb69401c0de32 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2043,6 +2043,8 @@ class JSObject: public JSReceiver {
   inline bool HasSlowArgumentsElements();
   inline bool HasFastStringWrapperElements();
   inline bool HasSlowStringWrapperElements();
+  bool HasEnumerableElements();
+
   inline SeededNumberDictionary* element_dictionary();  // Gets slow elements.
 
   // Requires: HasFastElements().
@@ -2294,6 +2296,9 @@ class JSObject: public JSReceiver {
 
   static Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object);
 
+  static Handle<FixedArray> GetFastEnumPropertyKeys(Isolate* isolate,
+                                                    Handle<JSObject> object);
+
   // Returns a new map with all transitions dropped from the object's current
   // map and the ElementsKind set.
   static Handle<Map> GetElementsTransitionMap(Handle<JSObject> object,