Example showing alternate async measurement solution

client/html/src/Document.dart

Index: client/html/src/Document.dart
diff --git a/client/html/src/Document.dart b/client/html/src/Document.dart
index 9a8892c0ce937b591e50e25663df8d35233bffdc..b81762a91491cf5cdee8e897ac3c2696a72eaaf8 100644
--- a/client/html/src/Document.dart
+++ b/client/html/src/Document.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.
 
@@ -59,9 +59,11 @@ interface Document extends Element /*, common.NodeSelector */ {
 
   String get webkitVisibilityState();
 
-  Future<Range> caretRangeFromPoint([int x, int y]);
+  /** Only call when [window.inMeasurementFrame] is true. */
+  Range caretRangeFromPoint([int x, int y]);
 
-  Future<Element> elementFromPoint([int x, int y]);
+  /** Only call when [window.inMeasurementFrame] is true. */
+  Element elementFromPoint([int x, int y]);
 
   bool execCommand([String command, bool userInterface, String value]);
 
@@ -84,6 +86,4 @@ interface Document extends Element /*, common.NodeSelector */ {
   void set manifest(String value);
 
   DocumentEvents get on();
-
-  Future<ElementRect> get rect();
 }