Remove some dead code from rendering/ folder

Source/core/rendering/RenderLayerClipper.h

Index: Source/core/rendering/RenderLayerClipper.h
diff --git a/Source/core/rendering/RenderLayerClipper.h b/Source/core/rendering/RenderLayerClipper.h
index fea7716fb0fa764ac6815fe02697cd16f562db91..37ffa0818d7075d4d67163ecfd6ee5b92204eecf 100644
--- a/Source/core/rendering/RenderLayerClipper.h
+++ b/Source/core/rendering/RenderLayerClipper.h
@@ -91,7 +91,6 @@ public:
     void setCompositingClipRectsDirty();
 
     LayoutRect childrenClipRect() const; // Returns the foreground clip rect of the layer in the document's coordinate space.
-    LayoutRect selfClipRect() const; // Returns the background clip rect of the layer in the document's coordinate space.
     LayoutRect localClipRect() const; // Returns the background clip rect of the layer in the local coordinate space.
 
     ClipRect backgroundClipRect(const ClipRectsContext&) const;