Layout API prototype, for discussion

sky/sdk/lib/framework/layout.dart

 library layout;
 
+// This version of layout.dart is a shim version of layout2.dart that is backed using CSS and <div>s.
+
 import 'node.dart';
 import 'dart:sky' as sky;
 import 'dart:collection';
 
 // UTILS
 
 // Bridge to legacy CSS-like style specification
 // Eventually we'll replace this with something else
 class Style {
   final String _className;
@@ skipping 44 matching lines @@
   void detach() {
     detachSiblings();
   }
   void detachSiblings() { } // workaround for lack of inter-class mixins in Dart
   void merge(ParentData other) {
     // override this in subclasses to merge in data from other into this
     assert(other.runtimeType == this.runtimeType);
   }
 }
 
-abstract class RenderNode extends Node {
+abstract class RenderNode extends AbstractNode {
 
   // LAYOUT
 
   // parentData is only for use by the RenderNode that actually lays this
   // node out, and any other nodes who happen to know exactly what
   // kind of node that is.
   ParentData parentData;
   void setupPos(RenderNode child) {
     // override this to setup .parentData correctly for your class
     if (child.parentData is! ParentData)
@@ skipping 473 matching lines @@
   print(prefix + node.toString() + _attributes(node));
   var children = node.getChildNodes();
   prefix = prefix + '  ';
   for (var child in children)
     _serialiseDOM(child, prefix);
 }
 
 void dumpState() {
   _serialiseDOM(sky.document);
 }