Remove some dead code from rendering/ folder

Source/core/rendering/compositing/RenderLayerCompositor.h

 /*
  * Copyright (C) 2009 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 254 matching lines @@
     void recursiveRepaintLayer(RenderLayer*);
 
     void computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer*, OverlapMap&, struct CompositingRecursionData&, bool& descendantHas3DTransform, Vector<RenderLayer*>& unclippedDescendants, IntRect& absoluteDecendantBoundingBox);
 
     // Defines which RenderLayers will paint into which composited backings, by allocating and destroying CompositedLayerMappings as needed.
     void assignLayersToBackings(RenderLayer*, bool& layersChanged);
     void assignLayersToBackingsInternal(RenderLayer*, SquashingState&, bool& layersChanged);
 
     // Hook compositing layers together
     void setCompositingParent(RenderLayer* childLayer, RenderLayer* parentLayer);
-    void removeCompositedChildren(RenderLayer*);
 
     bool hasAnyAdditionalCompositedLayers(const RenderLayer* rootLayer) const;
 
     void ensureRootLayer();
     void destroyRootLayer();
 
     void attachRootLayer(RootLayerAttachment);
     void detachRootLayer();
 
     void updateOverflowControlsLayers();
@@ skipping 64 matching lines @@
     OwnPtr<GraphicsLayer> m_layerForVerticalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForScrollCorner;
 #if USE(RUBBER_BANDING)
     OwnPtr<GraphicsLayer> m_layerForOverhangShadow;
 #endif
 };
 
 } // namespace WebCore
 
 #endif // RenderLayerCompositor_h