Implement measurement using futures

client/html/src/Document.dart

 // Copyright (c) 2011, 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();
 }
 
@@ skipping 25 matching lines @@
   void set cookie(String value);
 
   Window get window();
 
   String get domain();
 
   HeadElement get head();
 
   String get lastModified();
 
-  // TODO(jacobr): remove once on.contentLoaded is changed to return a Promise.
+  // TODO(jacobr): remove once on.contentLoaded is changed to return a Future.
   String get readyState();
 
   String get referrer();
 
   StyleSheetList get styleSheets();
 
   // 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();
 
-  Promise<Range> caretRangeFromPoint([int x, int y]);
+  Future<Range> caretRangeFromPoint([int x, int y]);
 
   // TODO(jacobr): remove.
   Element createElement([String tagName]);
 
-  Promise<Element> elementFromPoint([int x, int y]);
+  Future<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();
 }