Walk render tree instead of render layers for paint.

sky/engine/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 422 matching lines @@
     void setHasLayer(bool hasLayer) { m_bitfields.setHasLayer(hasLayer); }
     void setHasTransform(bool hasTransform) { m_bitfields.setHasTransform(hasTransform); }
     void setHasBoxDecorationBackground(bool b) { m_bitfields.setHasBoxDecorationBackground(b); }
 
     void scheduleRelayout();
 
     void updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers);
     void updateImage(StyleImage*, StyleImage*);
 
     // paintOffset is the offset from the origin of the GraphicsContext at which to paint the current object.
-    virtual void paint(PaintInfo&, const LayoutPoint& paintOffset);
+    virtual void paint(PaintInfo&, const LayoutPoint& paintOffset, Vector<RenderBox*>& layers);
 
     // Subclasses must reimplement this method to compute the size and position
     // of this object and all its descendants.
     virtual void layout() = 0;
 
     /* This function performs a layout only if one is needed. */
     void layoutIfNeeded() { if (needsLayout()) layout(); }
 
     void forceLayout();
     void forceChildLayout();
@@ skipping 462 matching lines @@
 void showTree(const blink::RenderObject*);
 void showLineTree(const blink::RenderObject*);
 void showRenderTree(const blink::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const blink::RenderObject* object1, const blink::RenderObject* object2);
 
 #endif
 
 #endif  // SKY_ENGINE_CORE_RENDERING_RENDEROBJECT_H_