Remove redundant 'flex' prefixes on enum values.

sky/sdk/lib/widgets/basic.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 'dart:async';
 import 'dart:sky' as sky;
 
 import 'package:vector_math/vector_math.dart';
 
 import '../mojo/asset_bundle.dart';
@@ skipping 384 matching lines @@
                                   ..bottom = bottom
                                   ..left = left,
              key: key);
 }
 
 class Flex extends MultiChildRenderObjectWrapper {
 
   Flex(List<Widget> children, {
     String key,
     this.direction: FlexDirection.horizontal,
-    this.justifyContent: FlexJustifyContent.flexStart,
+    this.justifyContent: FlexJustifyContent.start,
     this.alignItems: FlexAlignItems.center
   }) : super(key: key, children: children);
 
   RenderFlex get root => super.root;
   RenderFlex createNode() => new RenderFlex(direction: this.direction);
 
   final FlexDirection direction;
   final FlexJustifyContent justifyContent;
   final FlexAlignItems alignItems;
 
@@ skipping 168 matching lines @@
   }
 
   void remove() {
     RenderObjectWrapper ancestor = findAncestorRenderObjectWrapper();
     assert(ancestor is RenderObjectWrapper);
     ancestor.detachChildRoot(this);
     super.remove();
   }
 
 }