Instead of applying a transform for every RenderObject, pass down an Offset for where to paint.

sky/sdk/lib/rendering/object.dart

Index: sky/sdk/lib/rendering/object.dart
diff --git a/sky/sdk/lib/rendering/object.dart b/sky/sdk/lib/rendering/object.dart
index 5811ee2c38ecece6dd35631502581e5f2e4ca74e..02995bd645f391dc9edd61fa2a7b9e330639a4f8 100644
--- a/sky/sdk/lib/rendering/object.dart
+++ b/sky/sdk/lib/rendering/object.dart
@@ -29,10 +29,8 @@ class ParentData {
 class RenderCanvas extends sky.Canvas {
   RenderCanvas(sky.PictureRecorder recorder, Size bounds) : super(recorder, bounds);
 
-  void paintChild(RenderObject child, Point position) {
-    translate(position.x, position.y);
-    child.paint(this);
-    translate(-position.x, -position.y);
+  void paintChild(RenderObject child, Point point) {
+    child.paint(this, point.toOffset());
   }
 }
 
@@ -245,7 +243,7 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
     assert(!debugDoingPaint);
     scheduler.ensureVisualUpdate();
   }
-  void paint(RenderCanvas canvas) { }
+  void paint(RenderCanvas canvas, Offset offset) { }
 
 
   // EVENTS