Update BoxDecoration and RenderParagraph to use sky.Color instead of int.

sky/tests/raw/render_box.dart

Index: sky/tests/raw/render_box.dart
diff --git a/sky/tests/raw/render_box.dart b/sky/tests/raw/render_box.dart
index bf44896174dd56ff6d721bd1174664aa77f25058..111beb41a42204dc07fb2fade654bdfa26d227cb 100644
--- a/sky/tests/raw/render_box.dart
+++ b/sky/tests/raw/render_box.dart
@@ -14,7 +14,7 @@ void main() {
   test("should size to render view", () {
     RenderSizedBox root = new RenderSizedBox(
       child: new RenderDecoratedBox(
-        decoration: new BoxDecoration(backgroundColor: 0xFF00FF00)
+        decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFF00FF00))
       )
     );
     TestView renderView = new TestView(child: root);