Revert "Example showing alternate async measurement solution"

client/touch/Scroller.dart

Index: client/touch/Scroller.dart
diff --git a/client/touch/Scroller.dart b/client/touch/Scroller.dart
index f125c747b1d7acf0202a9e3383ffb52542808310..a9da0ebd72d9cab8ab7d61816c5351d6f8c23dc1 100644
--- a/client/touch/Scroller.dart
+++ b/client/touch/Scroller.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
@@ -32,6 +32,21 @@
  */
 typedef void Callback();
 
+// Helper method to await the completion of 2 futures.
+void joinFutures(List<Future> futures, Callback callback) {
+  int count = 0;
+  int len = futures.length;
+  void helper(value) {
+    count++;
+    if (count == len) {
+      callback();
+    }
+  }
+  for (Future p in futures) {
+    p.then(helper);
+  }
+}
+
 class Scroller implements Draggable, MomentumDelegate {
 
   /** Pixels to move each time an arrow key is pressed. */
@@ -216,8 +231,8 @@ class Scroller implements Draggable, MomentumDelegate {
     // The scrollable element must be relatively positioned.
     // TODO(jacobr): this assert fires asynchronously which could be confusing.
     if (_scrollTechnique == ScrollerScrollTechnique.RELATIVE_POSITIONING) {
-      window.requestMeasurementFrame(() {
-        assert(_element.computedStyle.position != "static");
+      _element.computedStyle.then((CSSStyleDeclaration style) {
+        assert(style.position != "static");
       });
     }
 
@@ -488,8 +503,6 @@ class Scroller implements Draggable, MomentumDelegate {
     reconfigure(() {
       final touch = e.touches[0];
       if (_momentum.decelerating) {
-        // TODO(jacobr): this won't do any good as it is called too late due
-        // to async measurement.
         e.preventDefault();
         e.stopPropagation();
         stop();
@@ -528,18 +541,24 @@ class Scroller implements Draggable, MomentumDelegate {
    * and maxPoint allowed for scrolling.
    */
   void _resize(Callback callback) {
-    window.requestMeasurementFrame(() {
-      final offset = _frame.rect.offset;
-
-      if (_lookupContentSizeDelegate !== null) {
-        // Guaranteed to be called within a measurement frame
-        _contentSize = _lookupContentSizeDelegate();
-      } else {
-        final scroll = _element.rect.scroll;
-        _contentSize = new Size(scroll.width, scroll.height);
-      }
+    final frameRect = _frame.rect;
+    Future contentSizeFuture;
 
-      _scrollSize = new Size(offset.width, offset.height);
+    if (_lookupContentSizeDelegate !== null) {
+      contentSizeFuture = _lookupContentSizeDelegate();
+      contentSizeFuture.then((Size size) {
+        _contentSize = size;
+      });
+    } else {
+      contentSizeFuture = _element.rect;
+      contentSizeFuture.then((ElementRect rect) {
+        _contentSize = new Size(rect.scroll.width, rect.scroll.height);
+      });
+    }
+
+    joinFutures(<Future>[frameRect, contentSizeFuture], () {
+      _scrollSize = new Size(frameRect.value.offset.width,
+                             frameRect.value.offset.height);
       Size adjusted = _getAdjustedContentSize();
       _maxPoint = new Coordinate(-_maxOffset.x, -_maxOffset.y);
       _minPoint = new Coordinate(
@@ -547,7 +566,7 @@ class Scroller implements Draggable, MomentumDelegate {
               _scrollSize.width - adjusted.width + _minOffset.x, _maxPoint.x),
           Math.min(
               _scrollSize.height - adjusted.height + _minOffset.y, _maxPoint.y));
-      return callback;
+      callback();
     });
   }