[ic] Data handlers for loads of non-existent properties.

src/ic/ic.h

Index: src/ic/ic.h
diff --git a/src/ic/ic.h b/src/ic/ic.h
index 00c4ee183d9d787f8ddb918b301ff14fbfe667aa..39036c42d6b0e9d86b474d1b6074cb11edd7f08b 100644
--- a/src/ic/ic.h
+++ b/src/ic/ic.h
@@ -311,22 +311,28 @@ class LoadIC : public IC {
                               CacheHolderFlag cache_holder) override;
 
  private:
+  // Creates a data handler that represents a load of a field by given index.
   Handle<Object> SimpleFieldLoad(FieldIndex index);
 
   // Returns 0 if the validity cell check is enough to ensure that the
   // prototype chain from |receiver_map| till |holder| did not change.
+  // If the |holder| is an empty handle then the full prototype chain is
+  // checked.
   // Returns -1 if the handler has to be compiled or the number of prototype
   // checks otherwise.
   int GetPrototypeCheckCount(Handle<Map> receiver_map, Handle<JSObject> holder);
 
   // Creates a data handler that represents a prototype chain check followed
   // by given Smi-handler that encoded a load from the holder.
-  // Can be used only if IsPrototypeValidityCellCheckEnough() predicate is true.
+  // Can be used only if GetPrototypeCheckCount() returns non negative value.
   Handle<Object> SimpleLoadFromPrototype(Handle<Map> receiver_map,
                                          Handle<JSObject> holder,
                                          Handle<Name> name,
                                          Handle<Object> smi_handler);
 
+  // Creates a data handler that represents a load of a non-existent property.
+  Handle<Object> SimpleLoadNonExistent(Handle<Map> receiver_map,
+                                       Handle<Name> name);
   friend class IC;
 };