diff --git a/platform.js b/platform.js
index 65aa67a..a440ee1 100644
--- a/platform.js
+++ b/platform.js
@@ -17,7 +17,7 @@ function processFlags(flags) {
     // truthy value for any of these flags, or failure to detect native
     // ShadowDOM, results in polyfill
     flags.shadow = (flags.shadowdom || flags.shadow || flags.polyfill ||
-      !HTMLElement.prototype.webkitCreateShadowRoot) && 'polyfill';
+      !HTMLElement.prototype.createShadowRoot) && 'polyfill';
 
     var ShadowDOMNative = [
       'src/patches-shadowdom-native.js'