Make rendering use PaintingNodes for increased efficiency.

sky/sdk/lib/rendering/box.dart

Index: sky/sdk/lib/rendering/box.dart
diff --git a/sky/sdk/lib/rendering/box.dart b/sky/sdk/lib/rendering/box.dart
index 78ec1d2c4d75075e52810734de486bb14c51c378..436dbb98a76283f949aec827ed07b2d7d28c327a 100644
--- a/sky/sdk/lib/rendering/box.dart
+++ b/sky/sdk/lib/rendering/box.dart
@@ -430,6 +430,8 @@ abstract class RenderBox extends RenderObject {
     _size = inDebugBuild ? new _DebugSize(value, this, debugCanParentUseSize) : value;
   }
 
+  Rect get paintBounds => Point.origin & size;
+
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}size: ${size}\n';
 }
 
@@ -489,7 +491,7 @@ class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox
 
   void paint(PaintingCanvas canvas, Offset offset) {
     if (child != null)
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
   }
 
 }
@@ -662,7 +664,7 @@ class RenderOpacity extends RenderProxyBox {
         return;
 
       if (a == 255) {
-        child.paint(canvas, offset);
+        canvas.paintChild(child, offset.toPoint());
         return;
       }
 
@@ -670,7 +672,7 @@ class RenderOpacity extends RenderProxyBox {
         ..color = new Color.fromARGB(a, 0, 0, 0)
         ..setTransferMode(sky.TransferMode.srcOver);
       canvas.saveLayer(null, paint);
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
       canvas.restore();
     }
   }
@@ -706,7 +708,7 @@ class RenderColorFilter extends RenderProxyBox {
       Paint paint = new Paint()
         ..setColorFilter(new sky.ColorFilter.mode(_color, _transferMode));
       canvas.saveLayer(null, paint);
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
       canvas.restore();
     }
   }
@@ -719,7 +721,7 @@ class RenderClipRect extends RenderProxyBox {
     if (child != null) {
       canvas.save();
       canvas.clipRect(offset & size);
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
       canvas.restore();
     }
   }
@@ -758,7 +760,7 @@ class RenderClipRRect extends RenderProxyBox {
       canvas.saveLayer(rect, new Paint());
       sky.RRect rrect = new sky.RRect()..setRectXY(rect, xRadius, yRadius);
       canvas.clipRRect(rrect);
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
       canvas.restore();
     }
   }
@@ -774,7 +776,7 @@ class RenderClipOval extends RenderProxyBox {
       Path path = new Path();
       path.addOval(rect);
       canvas.clipPath(path);
-      child.paint(canvas, offset);
+      canvas.paintChild(child, offset.toPoint());
       canvas.restore();
     }
   }
@@ -1143,6 +1145,8 @@ class RenderDecoratedBox extends RenderProxyBox {
 }
 
 class RenderTransform extends RenderProxyBox {
+  bool get createNewDisplayList => true;
+
   RenderTransform({
     Matrix4 transform,
     RenderBox child
@@ -1286,6 +1290,7 @@ class ViewConstraints {
 }
 
 class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox> {
+  bool get createNewDisplayList => true;
 
   RenderView({
     RenderBox child,
@@ -1352,18 +1357,17 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
 
   void paintFrame() {
     sky.tracing.begin('RenderView.paintFrame');
-    RenderObject.debugDoingPaint = true;
     try {
       sky.PictureRecorder recorder = new sky.PictureRecorder();
-      PaintingCanvas canvas = new PaintingCanvas(recorder, _size);
-      paint(canvas, Offset.zero);
+      PaintingCanvas canvas = new PaintingCanvas(recorder, paintBounds);
+      canvas.drawPaintingNode(paintingNode, Point.origin);
       sky.view.picture = recorder.endRecording();
     } finally {
-      RenderObject.debugDoingPaint = false;
       sky.tracing.end('RenderView.paintFrame');
     }
   }
 
+  Rect get paintBounds => Point.origin & size;
 }
 
 // HELPER METHODS FOR RENDERBOX CONTAINERS