Introduce Node::needsDistributionRecalc and use it in ElementShadow to fix the wrong assertions.

Source/core/dom/shadow/ElementShadow.cpp

Index: Source/core/dom/shadow/ElementShadow.cpp
diff --git a/Source/core/dom/shadow/ElementShadow.cpp b/Source/core/dom/shadow/ElementShadow.cpp
index ee565a50aa5bab72fa1e5ecd1c304e54e49e05be..48cabb20f559fa8b54a2cbf53c0566f9c9b03cc5 100644
--- a/Source/core/dom/shadow/ElementShadow.cpp
+++ b/Source/core/dom/shadow/ElementShadow.cpp
@@ -240,7 +240,7 @@ bool ElementShadow::hasSameStyles(const ElementShadow* other) const
 
 const InsertionPoint* ElementShadow::finalDestinationInsertionPointFor(const Node* key) const
 {
-    ASSERT(key && !key->document().childNeedsDistributionRecalc());
+    ASSERT(key && !key->needsDistributionRecalc());
     NodeToDestinationInsertionPoints::const_iterator it = m_nodeToInsertionPoints.find(key);
 #if ENABLE(OILPAN)
     return it == m_nodeToInsertionPoints.end() ? nullptr : it->value->last().get();
@@ -251,7 +251,7 @@ const InsertionPoint* ElementShadow::finalDestinationInsertionPointFor(const Nod
 
 const DestinationInsertionPoints* ElementShadow::destinationInsertionPointsFor(const Node* key) const
 {
-    ASSERT(key && !key->document().childNeedsDistributionRecalc());
+    ASSERT(key && !key->needsDistributionRecalc());
     NodeToDestinationInsertionPoints::const_iterator it = m_nodeToInsertionPoints.find(key);
 #if ENABLE(OILPAN)
     return it == m_nodeToInsertionPoints.end() ? nullptr : it->value.get();