Example showing alternate async measurement solution

client/html/release/html.dart

 #library('html');
 
 #import('dart:dom', prefix:'dom');
 #import('dart:htmlimpl');
 // 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.
 
 // DO NOT EDIT
 // Auto-generated Dart HTML library.
@@ skipping 11276 matching lines @@
 
   DeviceOrientationEvent(String type, double alpha, double beta, double gamma,
       [bool canBubble, bool cancelable]);
 
   num get alpha();
 
   num get beta();
 
   num get gamma();
 }
-// 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();
 }
 // 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 DocumentFragment extends Element default DocumentFragmentWrappingImplementation {
  
   DocumentFragment();
 
   DocumentFragment.html(String html);
@@ skipping 30 matching lines @@
   static final int UPDATEREADY = 4;
 
   int get status();
 
   void swapCache();
 
   void update();
 
   DOMApplicationCacheEvents get on();
 }
-// 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 ElementList extends List<Element> {
   // TODO(jacobr): add element batch manipulation methods.
   Element get first();
   // TODO(jacobr): add insertAt
 }
 
-class DeferredElementRect {
-  // TODO(jacobr)
-}
-
 interface ElementEvents extends Events {
   EventListenerList get abort();
   EventListenerList get beforeCopy();
   EventListenerList get beforeCut();
   EventListenerList get beforePaste();
   EventListenerList get blur();
   EventListenerList get change();
   EventListenerList get click();
   EventListenerList get contextMenu();
   EventListenerList get copy();
@@ skipping 153 matching lines @@
   Element get parent();
 
   void scrollByLines([int lines]);
 
   void scrollByPages([int pages]);
 
   void scrollIntoView([bool centerIfNeeded]);
 
   bool matchesSelector([String selectors]);
 
-  Future<ElementRect> get rect();
+  /** Only access members when [window.inMeasurementFrame] is true. */
+  ElementRect get rect();
 
-  Future<CSSStyleDeclaration> get computedStyle();
+  /** Only call when [window.inMeasurementFrame] is true. */
+  CSSStyleDeclaration get computedStyle();
 
-  Future<CSSStyleDeclaration> getComputedStyle(String pseudoElement);
+  /** Only call when [window.inMeasurementFrame] is true. */
+  CSSStyleDeclaration getComputedStyle(String pseudoElement);
 
   ElementEvents get on();
 
   Element clone(bool deep);
 }
 // 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 ErrorEvent extends Event default ErrorEventWrappingImplementation {
@@ skipping 842 matching lines @@
   int get attrChange();
 
   String get attrName();
 
   String get newValue();
 
   String get prevValue();
 
   Node get relatedNode();
 }
-// 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.
 
 // TODO(jacobr): stop extending eventTarget.
 interface Node extends EventTarget {
 
   NodeList get nodes();
 
   // TODO: The type of value should be Collection<Node>. See http://b/5392897
   void set nodes(value);
@@ skipping 15 matching lines @@
   Node remove();
 
   bool contains(Node otherNode);
 
   // TODO(jacobr): remove when/if Array supports a method similar to
   // insertBefore or we switch NodeList to implement LinkedList rather than
   // array.
   Node insertBefore(Node newChild, Node refChild);
 
   Node clone(bool deep);
+
+  bool get _inDocument();
 }
 // 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 NodeList extends List<Node> {
   Node get first();
 }
 // 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
@@ skipping 524 matching lines @@
   int get wheelDelta();
 
   int get wheelDeltaX();
 
   int get wheelDeltaY();
 
   int get x();
 
   int get y();
 }
-// 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.
 
+typedef void LayoutCallback();
+typedef LayoutCallback MeasurementCallback(); 
+
 interface WindowEvents extends Events {
   EventListenerList get abort();
   EventListenerList get beforeUnload();
   EventListenerList get blur();
   EventListenerList get canPlay();
   EventListenerList get canPlayThrough();
   EventListenerList get change();
   EventListenerList get click();
   EventListenerList get contextMenu();
   EventListenerList get dblClick();
@@ skipping 279 matching lines @@
   int setInterval(TimeoutHandler handler, int timeout);
 
   int setTimeout(TimeoutHandler handler, int timeout);
 
   Object showModalDialog(String url, [Object dialogArgs, String featureArgs]);
 
   void stop();
 
   void webkitCancelRequestAnimationFrame(int id);
 
-  // TODO(jacobr): make these return Future<Point>.
   Point webkitConvertPointFromNodeToPage([Node node, Point p]);
-
   Point webkitConvertPointFromPageToNode([Node node, Point p]);
 
   int webkitRequestAnimationFrame(RequestAnimationFrameCallback callback, [Element element]);
 
   /**
-   * Executes a [callback] after the next batch of browser layout measurements
-   * has completed or would have completed if any browser layout measurements
-   * had been scheduled.
+   * Executes [callback] after the event loop unwinds but before the page is
+   * rendered.  Inside the callback, synchronous element measurement is
+   * allowed and dom manipulation that could trigger a layout is disallowed.
+   * The [callback] may return a closure that is run in the normal
+   * context where dom manipulation is allowed but sync measurement is
+   * disallowed.
    */
-  void requestLayoutFrame(TimeoutHandler callback);
+  void requestMeasurementFrame(MeasurementCallback callback);
+
+  /**
+   * True iff within a call to [:requestMeasurementFrame:]
+   * When inside a measurement frame, any DOM manipulation that could trigger
+   * a layout is prohibited to avoid accidentally triggering large numbers of
+   * layouts.
+   */
+  bool get inMeasurementFrame();
 
   // Window open(String url, String target, WindowSpec features);
 
   WindowEvents get on();
 }
 // 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 WorkerEvents extends AbstractWorkerEvents {  
@@ skipping 95 matching lines @@
   EventListenerList get abort();
   EventListenerList get error();
   EventListenerList get load();
   EventListenerList get loadStart();
   EventListenerList get progress();
 }
 
 interface XMLHttpRequestUpload extends EventTarget {
   XMLHttpRequestUploadEvents get on();
 }