Removed funky Maybe constructor and made fields private.

src/api-natives.cc

Index: src/api-natives.cc
diff --git a/src/api-natives.cc b/src/api-natives.cc
index ed434caa004e73d64890a2cf261afffc5322a16a..44b09dffba387bc60d355a763b484554a949ccd1 100644
--- a/src/api-natives.cc
+++ b/src/api-natives.cc
@@ -81,14 +81,14 @@ MaybeHandle<Object> DefineDataProperty(Isolate* isolate,
     LookupIterator it(object, Handle<Name>::cast(key),
                       LookupIterator::OWN_SKIP_INTERCEPTOR);
     Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
-    DCHECK(maybe.has_value);
+    DCHECK(maybe.IsJust());
     duplicate = it.IsFound();
   } else {
     uint32_t index = 0;
     key->ToArrayIndex(&index);
     Maybe<bool> maybe = JSReceiver::HasOwnElement(object, index);
-    if (!maybe.has_value) return MaybeHandle<Object>();
-    duplicate = maybe.value;
+    if (!maybe.IsJust()) return MaybeHandle<Object>();
+    duplicate = maybe.FromJust();
   }
   if (duplicate) {
     Handle<Object> args[1] = {key};