Make rendering use PaintingNodes for increased efficiency.

sky/engine/core/painting/Canvas.cpp

 // 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.
 
 #include "math.h"
 
 #include "sky/engine/core/painting/Canvas.h"
 
 #include "sky/engine/core/dom/Document.h"
 #include "sky/engine/core/dom/Element.h"
@@ skipping 189 matching lines @@
 }
 
 void Canvas::drawDrawable(Drawable* drawable)
 {
     if (!m_canvas)
         return;
     ASSERT(drawable);
     m_canvas->drawDrawable(drawable->toSkia());
 }
 
+void Canvas::drawPaintingNode(PaintingNode* paintingNode)
+{
+    if (!m_canvas)
+        return;
+    ASSERT(paintingNode);
+    m_canvas->drawDrawable(paintingNode->toSkia());
+}
+
 } // namespace blink