Example showing alternate async measurement solution

client/html/src/SVGElementWrappingImplementation.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class _SVGClassSet extends _CssClassSet {
   _SVGClassSet(element) : super(element);
 
   String _className() => _element.className.baseVal;
 
   void _write(Set s) {
     _element.className.baseVal = _formatSet(s);
@@ skipping 25 matching lines @@
 
   Set<String> get classes() {
     if (_cssClassSet === null) {
       _cssClassSet = new _SVGClassSet(_ptr);
     }
     return _cssClassSet;
   }
 
   String get id() { return _ptr.id; }
 
-  void set id(String value) { _ptr.id = value; }
+  void set id(String value) {
+    assert(!_inMeasurementFrame || !_inDocument);
+    _ptr.id = value;
+  }
 
   SVGSVGElement get ownerSVGElement() { return LevelDom.wrapSVGSVGElement(_ptr.ownerSVGElement); }
 
   SVGElement get viewportElement() { return LevelDom.wrapSVGElement(_ptr.viewportElement); }
 
   String get xmlbase() { return _ptr.xmlbase; }
 
-  void set xmlbase(String value) { _ptr.xmlbase = value; }
+  void set xmlbase(String value) {
+    assert(!_inMeasurementFrame || !_inDocument);
+    _ptr.xmlbase = value;
+  }
 
   ElementList get elements() {
     if (_elements == null) {
       _elements = new FilteredElementList(this);
     }
     return _elements;
   }
 
   // TODO: The type of value should be Collection<Element>. See http://b/5392897
   void set elements(value) {
+    assert(!_inMeasurementFrame || !_inDocument);
     final elements = this.elements;
     elements.clear();
     elements.addAll(value);
   }
 
   String get outerHTML() {
     final container = new Element.tag("div");
     container.elements.add(this.clone(true));
     return container.innerHTML;
   }
 
   String get innerHTML() {
     final container = new Element.tag("div");
     container.elements.addAll(this.clone(true).elements);
     return container.innerHTML;
   }
 
   void set innerHTML(String svg) {
+    assert(!_inMeasurementFrame || !_inDocument);
     var container = new Element.tag("div");
     // Wrap the SVG string in <svg> so that SVGElements are created, rather than
     // HTMLElements.
     container.innerHTML = '<svg version="1.1">$svg</svg>';
     this.elements = container.elements.first.elements;
   }
 
   SVGElement clone(bool deep) => super.clone(deep);
 }