Alternate way to track first paint

Source/core/rendering/RenderView.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 69 matching lines @@
 
     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;
+    void invalidatePaintForRectangle(const LayoutRect&, InvalidationReason) const;
 
     void invalidatePaintForViewAndCompositedLayers();
 
     virtual void paint(PaintInfo&, const LayoutPoint&) OVERRIDE;
     virtual void paintBoxDecorationBackground(PaintInfo&, const LayoutPoint&) OVERRIDE;
 
     enum SelectionPaintInvalidationMode { PaintInvalidationNewXOROld, PaintInvalidationNewMinusOld, PaintInvalidationNothing };
     void setSelection(RenderObject* start, int startPos, RenderObject*, int endPos, SelectionPaintInvalidationMode = PaintInvalidationNewXOROld);
     void getSelection(RenderObject*& startRenderer, int& startOffset, RenderObject*& endRenderer, int& endOffset) const;
     void clearSelection();
@@ skipping 127 matching lines @@
             m_paintInvalidationState->m_cachedOffsetsEnabled = true;
     }
 private:
     const PaintInvalidationState* m_paintInvalidationState;
     bool m_didDisable;
 };
 
 } // namespace blink
 
 #endif // RenderView_h