Generalize paint chunks to clips, and implement clips in LayerPainter.

Source/core/rendering/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2121 matching lines @@
         LayerPaintingInfo paintingInfo(paintInfo.renderLayer, dirtyRect, PaintBehaviorNormal, paintInfo.renderLayer->subpixelAccumulation());
         LayerPainter(*paintInfo.renderLayer).paintLayerContents(context, paintingInfo, paintLayerFlags);
 
         if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
 
 #ifndef NDEBUG
             context->fillRect(dirtyRect, Color(0xFF, 0, 0));
 #endif
 
             if (RenderView* view = paintInfo.renderLayer->renderer()->view()) {
-                const PaintCommandList& paintCommandList = view->viewDisplayList().paintCommandList();
-                for (PaintCommandList::const_iterator it = paintCommandList.begin(); it != paintCommandList.end(); ++it)
-                    context->drawDisplayList(it->get()->displayList.get());
+                const PaintList& paintList = view->viewDisplayList().paintList();
+                for (PaintList::const_iterator it = paintList.begin(); it != paintList.end(); ++it)
+                    (*it)->replay(context);
             }
         }
 
         if (paintInfo.renderLayer->containsDirtyOverlayScrollbars())
             LayerPainter(*paintInfo.renderLayer).paintLayerContents(context, paintingInfo, paintLayerFlags | PaintLayerPaintingOverlayScrollbars);
     } else {
         ASSERT(compositor()->layerSquashingEnabled());
         LayerPaintingInfo paintingInfo(paintInfo.renderLayer, dirtyRect, PaintBehaviorNormal, paintInfo.renderLayer->subpixelAccumulation());
 
         // RenderLayer::paintLayer assumes that the caller clips to the passed rect. Squashed layers need to do this clipping in software,
@@ skipping 218 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink