Remove the |style| parameter from Material

sky/framework/components/popup_menu.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'animated_component.dart';
 import '../animation/animated_value.dart';
 import '../fn.dart';
 import '../theme/colors.dart';
 import '../theme/view-configuration.dart';
 import 'dart:async';
@@ skipping 69 matching lines @@
     });
   }
 
   Node build() {
     int i = 0;
     List<Node> children = new List.from(items.map((List<Node> item) {
       double opacity = _opacityFor(i);
       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);
   }
 }