Add a basic custom painting facility to Sky

sky/engine/platform/graphics/filters/SourceGraphic.cpp

 /*
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2013 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 45 matching lines @@
     if (!resultImage || !filter->sourceImage())
         return;
 
     IntRect srcRect = filter->sourceImageRect();
     if (ImageBuffer* sourceImageBuffer = filter->sourceImage()) {
         resultImage->context()->drawImageBuffer(sourceImageBuffer,
             FloatRect(IntPoint(srcRect.location() - absolutePaintRect().location()), sourceImageBuffer->size()));
     }
 }
 
-void SourceGraphic::setDisplayList(PassRefPtr<DisplayList> displayList)
-{
-    m_displayList = displayList;
-}
-
 PassRefPtr<SkImageFilter> SourceGraphic::createImageFilter(SkiaImageFilterBuilder*)
 {
-    if (!m_displayList)
-        return nullptr;
-
-    return adoptRef(SkPictureImageFilter::Create(m_displayList->picture(), m_displayList->bounds()));
+    return nullptr;
 }
 
 TextStream& SourceGraphic::externalRepresentation(TextStream& ts, int indent) const
 {
     writeIndent(ts, indent);
     ts << "[SourceGraphic]\n";
     return ts;
 }
 
 } // namespace blink