Support slotchange event

third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp

Index: third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp
diff --git a/third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp b/third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp
index 547c347e944e71b7dc9e5455d27c47c575dcf186..0c07782b4795e466bfe2ce58a9d0b1cfec97efe4 100644
--- a/third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/InsertionPoint.cpp
@@ -36,6 +36,7 @@
 #include "core/dom/QualifiedName.h"
 #include "core/dom/StaticNodeList.h"
 #include "core/dom/StyleChangeReason.h"
+#include "core/dom/StyleEngine.h"
 #include "core/dom/shadow/ElementShadow.h"
 
 namespace blink {
@@ -188,8 +189,11 @@ void InsertionPoint::childrenChanged(const ChildrenChange& change)
 {
     HTMLElement::childrenChanged(change);
     if (ShadowRoot* root = containingShadowRoot()) {
-        if (ElementShadow* rootOwner = root->owner())
+        if (ElementShadow* rootOwner = root->owner()) {
             rootOwner->setNeedsDistributionRecalc();
+            if (document().shadowCascadeOrder() == ShadowCascadeOrder::ShadowCascadeV1)
+                document().updateAssignment();
+        }
     }
 }
 
@@ -199,6 +203,8 @@ Node::InsertionNotificationRequest InsertionPoint::insertedInto(ContainerNode* i
     if (ShadowRoot* root = containingShadowRoot()) {
         if (ElementShadow* rootOwner = root->owner()) {
             rootOwner->setNeedsDistributionRecalc();
+            if (document().shadowCascadeOrder() == ShadowCascadeOrder::ShadowCascadeV1)
+                document().updateAssignment();
             if (canBeActive() && !m_registeredWithShadowRoot && insertionPoint->treeScope().rootNode() == root) {
                 m_registeredWithShadowRoot = true;
                 root->didAddInsertionPoint(this);
@@ -222,8 +228,11 @@ void InsertionPoint::removedFrom(ContainerNode* insertionPoint)
         root = insertionPoint->containingShadowRoot();
 
     if (root) {
-        if (ElementShadow* rootOwner = root->owner())
+        if (ElementShadow* rootOwner = root->owner()) {
             rootOwner->setNeedsDistributionRecalc();
+            if (document().shadowCascadeOrder() == ShadowCascadeOrder::ShadowCascadeV1)
+                document().updateAssignment();
+        }
     }
 
     // host can be null when removedFrom() is called from ElementShadow destructor.