Fix bustage from my previous CL: "Color.fromARGB" becomes "new Color.fromARGB".

sky/examples/raw/circle.sky

Index: sky/examples/raw/circle.sky
diff --git a/sky/examples/raw/circle.sky b/sky/examples/raw/circle.sky
index c5818c6aec6aacddd9e4c55c3feeaedba4d9bca5..dcf725492289c81093450866a84be6a7c1b6238f 100644
--- a/sky/examples/raw/circle.sky
+++ b/sky/examples/raw/circle.sky
@@ -14,7 +14,7 @@ void main() {
   var element = document.getElementById('canvas');
   element.requestPaint((PaintingContext context) {
     Paint paint = new Paint();
-    paint.color = Color.fromARGB(128, 0, 255, 0);
+    paint.color = const Color.fromARGB(128, 0, 255, 0);
     double radius = math.min(context.width, context.height) / 2.0;
     context.drawCircle(context.width / 2.0, context.height / 2.0, radius, paint);
     context.commit();