Remove a bunch of frame-level scrolling machinery.

sky/engine/core/rendering/RenderView.h

Index: sky/engine/core/rendering/RenderView.h
diff --git a/sky/engine/core/rendering/RenderView.h b/sky/engine/core/rendering/RenderView.h
index 36cc69e3b74c2c1f80a07f7b46c872557b60282b..96223e339620d59ae452c5bb29a523ed2c237b84 100644
--- a/sky/engine/core/rendering/RenderView.h
+++ b/sky/engine/core/rendering/RenderView.h
@@ -78,11 +78,6 @@ public:
 
     FrameView* frameView() const { return m_frameView; }
 
-    enum ViewportConstrainedPosition {
-        IsNotFixedPosition,
-        IsFixedPosition,
-    };
-    void mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect&, ViewportConstrainedPosition, const PaintInvalidationState*) const;
     virtual void mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect&, const PaintInvalidationState*) const override;
 
     void invalidatePaintForRectangle(const LayoutRect&) const;