Make FixedHeightScrollable understand heights

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 403 matching lines @@
     : super(child: child, key: key);
 
   RenderTransform createNode() => new RenderTransform(transform: transform);
 
   void syncRenderObject(Transform old) {
     super.syncRenderObject(old);
     root.transform = transform;
   }
 }
 
+class SizeObserver extends OneChildRenderObjectWrapper {
+  RenderSizeObserver root;
+  final SizeChangedCallback callback;
+
+  SizeObserver({ this.callback, UINode child, Object key })
+    : super(child: child, key: key);
+
+  RenderSizeObserver createNode() => new RenderSizeObserver(callback: callback);
+
+  void syncRenderObject(SizeObserver old) {
+    super.syncRenderObject(old);
+    root.callback = callback;
+  }
+}

[Hixie, 2015/06/04 20:35:50]

Should probably drop the callback when the child is removed, too, in case the
RenderObject is actually used for something else later and ends up calling us
unexpectedly.

[abarth-chromium, 2015/06/04 20:41:25]

Done.

+
+
 final List<UINode> _emptyList = new List<UINode>();
 
 abstract class MultiChildRenderObjectWrapper extends RenderObjectWrapper {
 
   // In MultiChildRenderObjectWrapper subclasses, slots are RenderObject nodes
   // to use as the "insert before" sibling in ContainerRenderObjectMixin.add() calls
 
   final List<UINode> children;
 
   MultiChildRenderObjectWrapper({
@@ skipping 529 matching lines @@
     assert(root.parent is RenderView);
   }
 }
 
 class Text extends Component {
   Text(this.data) : super(key: '*text*');
   final String data;
   bool get interchangeable => true;
   UINode build() => new Paragraph(text: data);
 }