Implement a simple checkbox in Sky’s fn2 components library

sky/engine/core/painting/Canvas.cpp

Index: sky/engine/core/painting/Canvas.cpp
diff --git a/sky/engine/core/painting/Canvas.cpp b/sky/engine/core/painting/Canvas.cpp
index ccd4fafaaab251d0ded2f7588551e66505796281..00552d94a452a6af88a4fbcf7b756f80d0f9dcfb 100644
--- a/sky/engine/core/painting/Canvas.cpp
+++ b/sky/engine/core/painting/Canvas.cpp
@@ -115,6 +115,15 @@ void Canvas::clipRect(const Rect& rect)
     m_canvas->clipRect(rect.sk_rect);
 }
 
+void Canvas::drawLine(float x0, float y0, float x1, float y1, const Paint* paint)
+{
+    if (!m_canvas)
+        return;
+    ASSERT(paint);
+    ASSERT(m_displayList->isRecording());
+    m_canvas->drawLine(x0, y0, x1, y1, paint->paint());
+}
+
 void Canvas::drawPicture(Picture* picture)
 {
     if (!m_canvas)
@@ -142,6 +151,16 @@ void Canvas::drawRect(const Rect& rect, const Paint* paint)
     m_canvas->drawRect(rect.sk_rect, paint->paint());
 }
 
+void Canvas::drawRRect(const RRect* rrect, const Paint* paint)
+{
+    if (!m_canvas)
+        return;
+    ASSERT(rrect);
+    ASSERT(paint);
+    ASSERT(m_displayList->isRecording());
+    m_canvas->drawRRect(rrect->rrect(), paint->paint());
+}
+
 void Canvas::drawOval(const Rect& rect, const Paint* paint)
 {
     if (!m_canvas)