Make the stocks popup menu fade in

sky/sdk/lib/framework/fn2.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.
 
 library fn;
 
 import 'app.dart';
 import 'dart:async';
 import 'dart:collection';
 import 'dart:mirrors';
@@ skipping 360 matching lines @@
   }
 
   void remove() {
     if (child != null)
       removeChild(child);
     super.remove();
   }
 
 }
 
+class Opacity extends OneChildRenderObjectWrapper {
+  Opacity({ this.opacity, UINode child, Object key })
+    : super(child: child, key: key);
+
+  RenderOpacity get root { RenderOpacity result = super.root; return result; }
+  final double opacity;
+
+  RenderOpacity createNode() => new RenderOpacity(opacity: opacity);
+
+  void syncRenderObject(Opacity old) {
+    super.syncRenderObject(old);
+    root.opacity = opacity;
+  }
+}
+
 class ClipRect extends OneChildRenderObjectWrapper {
 
   ClipRect({ UINode child, Object key })
     : super(child: child, key: key);
 
   RenderClipRect get root { RenderClipRect result = super.root; return result; }
   RenderClipRect createNode() => new RenderClipRect();
 }
 
 class ClipOval extends OneChildRenderObjectWrapper {
@@ skipping 789 matching lines @@
       // we haven't attached it yet
       assert(_container.child == null);
       _container.child = root;
     }
     assert(root.parent == _container);
   }
 
   UINode build() => builder();
 
 }