Implement measurement using futures

client/touch/Scrollbar.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.
 
 /**
  * Implementation of a scrollbar for the custom scrolling behavior
  * defined in [:Scroller:].
  */
 class Scrollbar implements ScrollListener {
   /**
@@ skipping 228 matching lines @@
       _onScrollerEnd(null);
     }
     updateScrollbars(scrollX, scrollY);
   }
 
   void refresh() {
     if (_scrollInProgress == false && _hovering == false) {
       // No need to refresh if not visible.
       return;
     }
-    _scroller._resize();
-    updateScrollbars(_scroller.getHorizontalOffset(),
-                     _scroller.getVerticalOffset());
+    _scroller._resize(() {
+      updateScrollbars(_scroller.getHorizontalOffset(),
+                       _scroller.getVerticalOffset());
+    });
   }
 
   void updateScrollbars(num scrollX, num scrollY) {
     Size contentSize = _scroller._getAdjustedContentSize();
     if (_scroller._shouldScrollHorizontally()) {
       num scrollPercentX = _scroller.getHorizontalScrollPercent(scrollX);
       _updateScrollbar(_horizontalElement, scrollX, scrollPercentX,
                        _scroller._scrollSize.width,
                        contentSize.width, 'right', 'width');
     }
@@ skipping 79 matching lines @@
     style.setProperty(cssPos, '${pos}px', '');
     if (_cachedSize[cssSize] != size) {
       _cachedSize[cssSize] = size;
       style.setProperty(cssSize, '${size}px', '');
     }
     if (element.parent == null) {
       _frame.nodes.add(element);
     }
   }
 }