Remove the |style| parameter from Material

sky/framework/components/popup_menu.dart

Index: sky/framework/components/popup_menu.dart
diff --git a/sky/framework/components/popup_menu.dart b/sky/framework/components/popup_menu.dart
index c3bf1afb15598b0dda0887511c17aa5c9cf3c3bd..d5a2e89939dda14362d64406fcc37e4f873e2b38 100644
--- a/sky/framework/components/popup_menu.dart
+++ b/sky/framework/components/popup_menu.dart
@@ -87,10 +87,11 @@ class PopupMenu extends AnimatedComponent {
       return new PopupMenuItem(key: i++, children: item, opacity: opacity);
     }));
 
-    return new Material(
-      style: _style,
-      inlineStyle: _inlineStyle(),
-      children: children,
-      level: level);
+    return new StyleNode(
+      new Material(
+        inlineStyle: _inlineStyle(),
+        children: children,
+        level: level),
+      _style);
   }
 }