Example showing alternate async measurement solution

client/html/src/DocumentFragmentWrappingImplementation.dart

Index: client/html/src/DocumentFragmentWrappingImplementation.dart
diff --git a/client/html/src/DocumentFragmentWrappingImplementation.dart b/client/html/src/DocumentFragmentWrappingImplementation.dart
index cea025fe819405bd6af155e81e841b5807c6f05d..843e918a230ceeebfa13c6c147eb35bac0e3a721 100644
--- a/client/html/src/DocumentFragmentWrappingImplementation.dart
+++ b/client/html/src/DocumentFragmentWrappingImplementation.dart
@@ -1,4 +1,4 @@
-// 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.
 
@@ -131,11 +131,6 @@ class EmptyStyleDeclaration extends CSSStyleDeclarationWrappingImplementation {
   }
 }
 
-Future<CSSStyleDeclaration> _emptyStyleFuture() {
-  return _createMeasurementFuture(() => new EmptyStyleDeclaration(),
-                                  new Completer<CSSStyleDeclaration>());
-}
-
 class EmptyElementRect implements ElementRect {
   final ClientRect client = const SimpleClientRect(0, 0, 0, 0);
   final ClientRect offset = const SimpleClientRect(0, 0, 0, 0);
@@ -233,9 +228,10 @@ class DocumentFragmentWrappingImplementation extends NodeWrappingImplementation
     return _on;
   }
 
-  Future<ElementRect> get rect() {
-    return _createMeasurementFuture(() => const EmptyElementRect(),
-                                    new Completer<ElementRect>());
+  ElementRect get rect() {
+    // A document fragment can never be attached to a Document so it always
+    // safe to measure.
+    return const EmptyElementRect();
   }
 
   Element query(String selectors) =>
@@ -268,10 +264,9 @@ class DocumentFragmentWrappingImplementation extends NodeWrappingImplementation
   Set<String> get classes() => new Set<String>();
   Map<String, String> get dataAttributes() => const {};
   CSSStyleDeclaration get style() => new EmptyStyleDeclaration();
-  Future<CSSStyleDeclaration> get computedStyle() =>
-      _emptyStyleFuture();
-  Future<CSSStyleDeclaration> getComputedStyle(String pseudoElement) =>
-      _emptyStyleFuture();
+  CSSStyleDeclaration get computedStyle() => new EmptyStyleDeclaration();
+  CSSStyleDeclaration getComputedStyle(String pseudoElement) =>
+      new EmptyStyleDeclaration();
   bool matchesSelector([String selectors]) => false;
 
   // Imperative Element methods are made into no-ops, as they are on parentless