[builtins] implement Array.prototype.includes in TurboFan

src/elements.h

Index: src/elements.h
diff --git a/src/elements.h b/src/elements.h
index ae48d4ef07257ef8504804c01a986842a977ca6b..a2fb0352cab91c576c73e84147d6b763dbeccf7f 100644
--- a/src/elements.h
+++ b/src/elements.h
@@ -154,6 +154,12 @@ class ElementsAccessor {
   virtual uint32_t GetCapacity(JSObject* holder,
                                FixedArrayBase* backing_store) = 0;
 
+  // Check an Object's own elements for an element (using SameValueZero
+  // semantics)
+  virtual Maybe<bool> IncludesValue(Isolate* isolate, Handle<JSObject> receiver,
+                                    Handle<Object> value, uint32_t start,
+                                    uint32_t length) = 0;
+
  protected:
   friend class LookupIterator;