Fix Sky issue where RenderNode was not painting automatically in interactive situations

sky/sdk/lib/framework/rendering/node.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 '../node.dart';
 import '../scheduler.dart' as scheduler;
 import 'dart:math' as math;
 import 'dart:sky' as sky;
 
 class ParentData {
@@ skipping 80 matching lines @@
       assert(debugAncestorsAlreadyMarkedNeedsLayout());
       return;
     }
     _needsLayout = true;
     assert(_relayoutSubtreeRoot != null);
     if (_relayoutSubtreeRoot != this) {
       assert(parent is RenderNode);
       parent.markNeedsLayout();
     } else {
       _nodesNeedingLayout.add(this);
+      scheduler.ensureVisualUpdate();
     }
   }
   static void flushLayout() {
     _debugDoingLayout = true;
     List<RenderNode> dirtyNodes = _nodesNeedingLayout;
     _nodesNeedingLayout = new List<RenderNode>();
     dirtyNodes..sort((a, b) => a.depth - b.depth)..forEach((node) {
       if (node._needsLayout && node.attached)
         node._doLayout();
     });
@@ skipping 271 matching lines @@
     }
   }
 
   ChildType get firstChild => _firstChild;
   ChildType get lastChild => _lastChild;
   ChildType childAfter(ChildType child) {
     assert(child.parentData is ParentDataType);
     return child.parentData.nextSibling;
   }
 }