Add GraphicsLayerDebugInfo::includesNewPaintInvalidation to distinguish paint from new RenderObjects

Source/core/rendering/RenderLayerRepainter.h

Index: Source/core/rendering/RenderLayerRepainter.h
diff --git a/Source/core/rendering/RenderLayerRepainter.h b/Source/core/rendering/RenderLayerRepainter.h
index c1768a43dc8839c299b7a2c37284e26ad03316fb..0736118de7ac0bb368cdb0310e149628265e62c5 100644
--- a/Source/core/rendering/RenderLayerRepainter.h
+++ b/Source/core/rendering/RenderLayerRepainter.h
@@ -67,6 +67,7 @@ public:
     // Indicate that the layer contents need to be repainted. Only has an effect
     // if layer compositing is being used,
     void setBackingNeedsPaintInvalidationInRect(const LayoutRect&); // r is in the coordinate space of the layer's render object
+    void setBackingIncludesFirstPaintInvalidation();
 
     void setFilterBackendNeedsPaintInvalidationInRect(const LayoutRect&);