Invalidate paint when allocating a DeprecatedPaintLayer.

Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 266 matching lines @@
             if (newStyleIsViewportConstained && layer())
                 frameView->addViewportConstrainedObject(this);
             else
                 frameView->removeViewportConstrainedObject(this);
         }
     }
 }
 
 void LayoutBoxModelObject::createLayer(DeprecatedPaintLayerType type)
 {
+
+    // Acquiring a DeprecatedPaintLayer may change the paint invalidation container. Therefore we must eagerly
+    // invalidate paint for this object before creating the layer.
+    if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled() && isRooted()) {
+        DisablePaintInvalidationStateAsserts invalidationDisabler;
+        DisableCompositingQueryAsserts compositingDisabler;
+
+        // It would be more correct to call invalidatePaintIncludingNonCompositingDescendants, but
+        // we do this instead to avoid performance issues when creating large numbers of layers.
+        const LayoutBoxModelObject& paintInvalidationContainer = containerForPaintInvalidationOnRootedTree();
+        invalidatePaintUsingContainer(
+            paintInvalidationContainer,
+            boundsRectForPaintInvalidation(&paintInvalidationContainer),
+            PaintInvalidationLayer);
+    }
+
     ASSERT(!m_layer);
     m_layer = adoptPtr(new DeprecatedPaintLayer(this, type));
     setHasLayer(true);
     m_layer->insertOnlyThisLayer();
 }
 
 void LayoutBoxModelObject::destroyLayer()
 {
     setHasLayer(false);
     m_layer = nullptr;
@@ skipping 718 matching lines @@
     if (rootElementStyle->hasBackground())
         return false;
 
     if (node() != document().firstBodyElement())
         return false;
 
     return true;
 }
 
 } // namespace blink