Bug 1758164 - Align the behavior of defining non-configurable properties on a WindowProxy on Nightly with Release/Beta; r=peterv

Differential Revision: https://phabricator.services.mozilla.com/D141732

dom/base/nsGlobalWindowOuter.cpp

@@ -574,28 +574,6 @@ void nsOuterWindowProxy::finalize(JS::GCContext* gcx, JSObject* proxy) const {
   }
 }
 
-/**
- * IsNonConfigurableReadonlyPrimitiveGlobalProp returns true for
- * property names that fit the following criteria:
- *
- * 1) The ES spec defines a property with that name on globals.
- * 2) The property is non-configurable.
- * 3) The property is non-writable (readonly).
- * 4) The value of the property is a primitive (so doesn't change
- *    observably on when navigation happens).
- *
- * Such properties can act as actual non-configurable properties on a
- * WindowProxy, because they are not affected by navigation.
- */
-#ifndef RELEASE_OR_BETA
-static bool IsNonConfigurableReadonlyPrimitiveGlobalProp(JSContext* cx,
-                                                         JS::Handle<jsid> id) {
-  return id == GetJSIDByIndex(cx, XPCJSContext::IDX_NAN) ||
-         id == GetJSIDByIndex(cx, XPCJSContext::IDX_UNDEFINED) ||
-         id == GetJSIDByIndex(cx, XPCJSContext::IDX_INFINITY);
-}
-#endif
-
 bool nsOuterWindowProxy::getOwnPropertyDescriptor(
     JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
     JS::MutableHandle<Maybe<JS::PropertyDescriptor>> desc) const {
@@ -651,7 +629,8 @@ bool nsOuterWindowProxy::getOwnPropertyDescriptor(
         return false;
       }
 
-#ifndef RELEASE_OR_BETA  // To be turned on in bug 1496510.
+#if 0
+      // See https://github.com/tc39/ecma262/issues/672 for more information.
       if (desc.isSome() &&
           !IsNonConfigurableReadonlyPrimitiveGlobalProp(cx, id)) {
         (*desc).setConfigurable(true);
@@ -768,7 +747,8 @@ bool nsOuterWindowProxy::definePropertySameOrigin(
     }
   }
 
-#ifndef RELEASE_OR_BETA  // To be turned on in bug 1496510.
+#if 0
+  // See https://github.com/tc39/ecma262/issues/672 for more information.
   if (desc.hasConfigurable() && !desc.configurable() &&
       !IsNonConfigurableReadonlyPrimitiveGlobalProp(cx, id)) {
     // Give callers a way to detect that they failed to "really" define a