Reduce the quality of the blur in the material shadows

sky/sdk/lib/painting/shadows.dart

Index: sky/sdk/lib/painting/shadows.dart
diff --git a/sky/sdk/lib/painting/shadows.dart b/sky/sdk/lib/painting/shadows.dart
index 1aa53737f7a88844d37c1f1ff893de46f3bf4be9..71248959df8d2e5eef9a55484d2f79559ba244e7 100644
--- a/sky/sdk/lib/painting/shadows.dart
+++ b/sky/sdk/lib/painting/shadows.dart
@@ -18,9 +18,7 @@ class ShadowDrawLooperBuilder {
           (sky.Paint layerPaint) {
         layerPaint.color = color;
         layerPaint.setMaskFilter(
-          new sky.MaskFilter.blur(sky.BlurStyle.normal,
-                                  blur,
-                                  highQuality: true));
+          new sky.MaskFilter.blur(sky.BlurStyle.normal, blur));
       });
   }