Clean up a bunch of our Dart code.

sky/sdk/lib/framework/components2/scrollable.dart

Index: sky/sdk/lib/framework/components2/scrollable.dart
diff --git a/sky/sdk/lib/framework/components2/scrollable.dart b/sky/sdk/lib/framework/components2/scrollable.dart
index 1bad1700f85e0c0c2d8220e6cf90d8e3c2a37146..bc76e4026345c1523dff20eeb3ea371b604d7bdc 100644
--- a/sky/sdk/lib/framework/components2/scrollable.dart
+++ b/sky/sdk/lib/framework/components2/scrollable.dart
@@ -23,6 +23,10 @@ abstract class ScrollClient {
 
 abstract class Scrollable extends Component {
 
+  Scrollable({Object key}) : super(key: key) {
+    onDidUnmount(_stopSimulation);
+  }
+
   double _scrollOffset = 0.0;
   double get scrollOffset => _scrollOffset;
 
@@ -36,10 +40,6 @@ abstract class Scrollable extends Component {
 
   Simulation _simulation;
 
-  Scrollable({Object key}) : super(key: key) {
-    onDidUnmount(_stopSimulation);
-  }
-
   UINode buildContent();
 
   UINode build() {
@@ -143,4 +143,5 @@ abstract class Scrollable extends Component {
   void _handleWheel(sky.WheelEvent event) {
     scrollBy(-event.offsetY);
   }
+
 }