Fix analyzer warning

sky/sdk/lib/widgets/material.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 '../animation/animation_performance.dart';
 import '../painting/box_painter.dart';
 import 'animated_component.dart';
 import 'animated_container.dart';
 import 'basic.dart';
 import 'default_text_style.dart';
@@ skipping 38 matching lines @@
 
   void syncFields(Material source) {
     child = source.child;
     _container.syncFields(source._container);
     super.syncFields(source);
   }
 
   AnimatedColor _getBackgroundColor(MaterialType type, Color color) {
     if (color == null) {
       switch (type) {
-        case MaterialType.canvas: color = Theme.of(this).canvasColor; break;
-        case MaterialType.card: color = Theme.of(this).cardColor; break;
+        case MaterialType.canvas:
+          color = Theme.of(this).canvasColor;
+          break;
+        case MaterialType.card:
+          color = Theme.of(this).cardColor;
+          break;
+        default:
+          break;
       }
     }
     return color == null ? null : new AnimatedColor(color);
   }
 
   Widget build() {
     return _container.build(
         new DefaultTextStyle(style: Theme.of(this).text.body1, child: child)
     );
   }
 
 }