Add GraphicsLayerDebugInfo::includesNewPaintInvalidation to distinguish paint from new RenderObjects

Source/core/rendering/RenderLayerRepainter.cpp

Index: Source/core/rendering/RenderLayerRepainter.cpp
diff --git a/Source/core/rendering/RenderLayerRepainter.cpp b/Source/core/rendering/RenderLayerRepainter.cpp
index 62336f563659bdeb02247c95cbe44d53d43ab0b1..a3e0b9ba7990b29a89a0f90dbb261d0c79cfb589 100644
--- a/Source/core/rendering/RenderLayerRepainter.cpp
+++ b/Source/core/rendering/RenderLayerRepainter.cpp
@@ -110,14 +110,25 @@ void RenderLayerRepainter::setBackingNeedsPaintInvalidationInRect(const LayoutRe
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,
     // so assert but check that the layer is composited.
     ASSERT(m_renderer.compositingState() != NotComposited);
+
+    bool firstPaint = !m_renderer.hadPaintInvalidation();
+    m_renderer.setHadPaintInvalidation();
+
     // FIXME: generalize accessors to backing GraphicsLayers so that this code is squashing-agnostic.
     if (m_renderer.layer()->groupedMapping()) {
         LayoutRect paintInvalidationRect = r;
         paintInvalidationRect.move(m_renderer.layer()->subpixelAccumulation());
-        if (GraphicsLayer* squashingLayer = m_renderer.layer()->groupedMapping()->squashingLayer())
+        if (GraphicsLayer* squashingLayer = m_renderer.layer()->groupedMapping()->squashingLayer()) {
             squashingLayer->setNeedsDisplayInRect(pixelSnappedIntRect(paintInvalidationRect));
+            if (firstPaint)
+                squashingLayer->setIncludesFirstPaintInvalidation();
+        }
     } else {
-        m_renderer.layer()->compositedLayerMapping()->setContentsNeedDisplayInRect(r);
+        CompositedLayerMapping* mapping = m_renderer.layer()->compositedLayerMapping();
+        ASSERT(mapping);
+        mapping->setContentsNeedDisplayInRect(r);
+        if (firstPaint)
+            mapping->mainGraphicsLayer()->setIncludesFirstPaintInvalidation();
     }
 }