Alternate way to track first paint

Source/core/rendering/RenderLayerModelObject.h

Index: Source/core/rendering/RenderLayerModelObject.h
diff --git a/Source/core/rendering/RenderLayerModelObject.h b/Source/core/rendering/RenderLayerModelObject.h
index c7a46650719104fd580fbea4b089bd42e677682a..667271c3affdededea74ae4a766bb0b498dc7020 100644
--- a/Source/core/rendering/RenderLayerModelObject.h
+++ b/Source/core/rendering/RenderLayerModelObject.h
@@ -67,7 +67,7 @@ public:
     virtual void invalidateTreeIfNeeded(const PaintInvalidationState&) OVERRIDE;
 
     // Indicate that the contents of this renderer need to be repainted. Only has an effect if compositing is being used,
-    void setBackingNeedsPaintInvalidationInRect(const LayoutRect&) const; // r is in the coordinate space of this render object
+    void setBackingNeedsPaintInvalidationInRect(const LayoutRect&, InvalidationReason) const; // r is in the coordinate space of this render object
 
 protected:
     void createLayer(LayerType);