Make it possible to Paint elements into a display list.

sky/engine/core/painting/Canvas.h

Index: sky/engine/core/painting/Canvas.h
diff --git a/sky/engine/core/painting/Canvas.h b/sky/engine/core/painting/Canvas.h
index 3775597ef87baf518b21e80e8bcbb72ba73c4b1b..a316f6592f69a73db1d072cd06a769deaa9833f2 100644
--- a/sky/engine/core/painting/Canvas.h
+++ b/sky/engine/core/painting/Canvas.h
@@ -42,6 +42,8 @@ public:
     void drawOval(const Vector<float>& rect, const Paint* paint);
     void drawCircle(float x, float y, float radius, Paint* paint);
 
+    SkCanvas* skCanvas() { return m_canvas; }
+
 protected:
     PassRefPtr<DisplayList> finishRecording();