Split Size into Size and Offset.

sky/sdk/lib/widgets/switch.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky' as sky;
 
 import 'package:sky/theme/shadows.dart';
 
 import '../painting/shadows.dart';
 import '../rendering/box.dart';
@@ skipping 48 matching lines @@
     for (BoxShadow boxShadow in shadows[1])
       builder.addShadow(boxShadow.offset, boxShadow.color, boxShadow.blur);
     paint.setDrawLooper(builder.build());
 
     // The thumb contracts slightly during the animation
     double inset = 2.0 - (toggleAnimation.value - 0.5).abs() * 2.0;
     Point thumbPos = new Point(
       _kTrackRadius + toggleAnimation.value * (_kTrackWidth - _kTrackRadius * 2),
       _kSwitchHeight / 2.0
     );
-    canvas.drawCircle(thumbPos.x, thumbPos.y, _kThumbRadius - inset, paint);
+    canvas.drawCircle(thumbPos, _kThumbRadius - inset, paint);
   }
 }