Remove some dead code from rendering/ folder

Source/core/rendering/compositing/RenderLayerCompositor.cpp

Index: Source/core/rendering/compositing/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/compositing/RenderLayerCompositor.cpp b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
index a8a42305b9ea99df19e8c87be5b54d9bc4a53dbd..5e9ad28cbfb1c39c54726bfe5abd9870d4e6ecfe 100644
--- a/Source/core/rendering/compositing/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
@@ -935,14 +935,6 @@ void RenderLayerCompositor::setCompositingParent(RenderLayer* childLayer, Render
     }
 }
 
-void RenderLayerCompositor::removeCompositedChildren(RenderLayer* layer)
-{
-    ASSERT(layer->hasCompositedLayerMapping());
-
-    GraphicsLayer* hostingLayer = layer->compositedLayerMapping()->parentForSublayers();
-    hostingLayer->removeAllChildren();
-}
-
 void RenderLayerCompositor::frameViewDidChangeLocation(const IntPoint& contentsOffset)
 {
     if (m_overflowControlsHostLayer)