Remove unused 3DTransformedDescendant methods.

Source/core/rendering/RenderLayer.h

Index: Source/core/rendering/RenderLayer.h
diff --git a/Source/core/rendering/RenderLayer.h b/Source/core/rendering/RenderLayer.h
index b3396ab51d33864707e4c88de4a90da7f75ae1b3..aa25f4d27113e86066368db11fa6166565cdd333 100644
--- a/Source/core/rendering/RenderLayer.h
+++ b/Source/core/rendering/RenderLayer.h
@@ -563,10 +563,6 @@ private:
 
     void updateDescendantDependentFlags();
 
-    // This flag is computed by RenderLayerCompositor, which knows more about 3d hierarchies than we do.
-    void setHas3DTransformedDescendant(bool b) { m_has3DTransformedDescendant = b; }
-    bool has3DTransformedDescendant() const { return m_has3DTransformedDescendant; }
-
     void dirty3DTransformedDescendantStatus();
     // Both updates the status, and returns true if descendants of this have 3d.
     bool update3DTransformedDescendantStatus();