Example showing alternate async measurement solution

client/html/src/Document.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.
 
 interface DocumentEvents extends ElementEvents {
   EventListenerList get readyStateChange();
   EventListenerList get selectionChange();
   EventListenerList get contentLoaded();
 }
 
 // TODO(jacobr): add DocumentFragment ctor
@@ skipping 40 matching lines @@
 
   // TODO(jacobr): should this be removed? Users could write document.query("title").text instead.
   String get title();
 
   void set title(String value);
 
   bool get webkitHidden();
 
   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]);
 
   // TODO(jacobr): remove once a new API is specified
   CanvasRenderingContext getCSSCanvasContext(String contextId, String name,
                                              int width, int height);
 
   bool queryCommandEnabled([String command]);
 
   bool queryCommandIndeterm([String command]);
 
   bool queryCommandState([String command]);
 
   bool queryCommandSupported([String command]);
 
   String queryCommandValue([String command]);
 
   String get manifest();
 
   void set manifest(String value);
 
   DocumentEvents get on();
-
-  Future<ElementRect> get rect();
 }