Changing window.requestLayoutFrame into a microtask API

samples/swarm/swarm_ui_lib/touch/Scroller.dart

Index: samples/swarm/swarm_ui_lib/touch/Scroller.dart
diff --git a/samples/swarm/swarm_ui_lib/touch/Scroller.dart b/samples/swarm/swarm_ui_lib/touch/Scroller.dart
index 196d910854e6e0f2a632bde7d101e7872526b291..7c21a692c64ba533c689c3b5c75250a8b701f33b 100644
--- a/samples/swarm/swarm_ui_lib/touch/Scroller.dart
+++ b/samples/swarm/swarm_ui_lib/touch/Scroller.dart
@@ -233,9 +233,7 @@ 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) {
-      _element.computedStyle.then((CssStyleDeclaration style) {
-        assert(style.position != "static");
-      });
+      assert(_element.getComputedStyle().position != "static");
     }
 
     _initLayer();
@@ -543,7 +541,7 @@ class Scroller implements Draggable, MomentumDelegate {
    * and maxPoint allowed for scrolling.
    */
   void _resize(Callback callback) {
-    window.requestLayoutFrame(() {
+    window.setImmediate(() {
       if (_lookupContentSizeDelegate != null) {
         _contentSize = _lookupContentSizeDelegate();
       } else {