Clean up a bunch of our Dart code.

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

Index: sky/sdk/lib/framework/components2/checkbox.dart
diff --git a/sky/sdk/lib/framework/components2/checkbox.dart b/sky/sdk/lib/framework/components2/checkbox.dart
index 1944d2e05429cec25e96ed6cf6226e16f3d89067..706dc6020c09aaaa529d390a217a650ef106707b 100644
--- a/sky/sdk/lib/framework/components2/checkbox.dart
+++ b/sky/sdk/lib/framework/components2/checkbox.dart
@@ -14,11 +14,11 @@ typedef void ValueChanged(value);
 
 class Checkbox extends ButtonBase {
 
+  Checkbox({ Object key, this.onChanged, this.checked }) : super(key: key);
+
   bool checked;
   ValueChanged onChanged;
 
-  Checkbox({ Object key, this.onChanged, this.checked }) : super(key: key);
-
   void _handleClick(sky.Event e) {
     onChanged(!checked);
   }
@@ -63,4 +63,5 @@ class Checkbox extends ButtonBase {
       onGestureTap: _handleClick
     );
   }
+
 }