Implement a simple checkbox in Sky’s fn2 components library

sky/engine/core/painting/RRect.idl

Index: sky/engine/core/painting/RRect.idl
diff --git a/sky/engine/core/painting/ColorFilter.idl b/sky/engine/core/painting/RRect.idl
similarity index 65%
copy from sky/engine/core/painting/ColorFilter.idl
copy to sky/engine/core/painting/RRect.idl
index 23d49f1a53042ae6bae9318bebb0a004fa0d9e50..16d83c73282ccd0c46b267d65ebd8bff8fa37cb7 100644
--- a/sky/engine/core/painting/ColorFilter.idl
+++ b/sky/engine/core/painting/RRect.idl
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 [
-  Constructor(Color color, TransferMode transferMode),
-] interface ColorFilter {
+  Constructor(),
+] interface RRect {
+  void setRectXY(Rect rect, float xRad, float yRad);

[abarth-chromium, 2015/06/05 21:00:59]

I was expecting this to be like Rect.dart, which is to say a Dart-native object
that coverts into an SkRRect

[jackson, 2015/06/05 21:14:11]

I think this class is complicated and rarely used enough that we don't need to
have a Dart-native version

 };