Support slotchange event

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

Index: third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
diff --git a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
index 1b204033c8bd1438d39c6d504460ad665338afa1..1f8e177be8841c4cb229f92dc91bb2caef731122 100644
--- a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
@@ -126,6 +126,8 @@ void ShadowRoot::attach(const AttachContext& context)
 Node::InsertionNotificationRequest ShadowRoot::insertedInto(ContainerNode* insertionPoint)
 {
     DocumentFragment::insertedInto(insertionPoint);
+    if (isV1())
+        document().updateAssignment();
 
     if (!insertionPoint->inShadowIncludingDocument() || !isOldest())
         return InsertionDone;
@@ -141,6 +143,7 @@ Node::InsertionNotificationRequest ShadowRoot::insertedInto(ContainerNode* inser
         m_registeredWithParentShadowRoot = true;
     }
 
+
     return InsertionDone;
 }
 
@@ -169,8 +172,11 @@ void ShadowRoot::childrenChanged(const ChildrenChange& change)
         checkForSiblingStyleChanges(change.type == ElementRemoved ? SiblingElementRemoved : SiblingElementInserted, change.siblingBeforeChange, change.siblingAfterChange);
 
     if (InsertionPoint* point = shadowInsertionPointOfYoungerShadowRoot()) {
-        if (ShadowRoot* root = point->containingShadowRoot())
+        if (ShadowRoot* root = point->containingShadowRoot()) {
             root->owner()->setNeedsDistributionRecalc();
+            if (document().shadowCascadeOrder() == ShadowCascadeOrder::ShadowCascadeV1)
+                document().updateAssignment();
+        }
     }
 }
 
@@ -334,13 +340,20 @@ const HeapVector<Member<HTMLSlotElement>>& ShadowRoot::descendantSlots()
     return m_shadowRootRareData->descendantSlots();
 }
 
-void ShadowRoot::distributeV1()
+void ShadowRoot::assignV1()
 {
     if (!m_slotAssignment)
         m_slotAssignment = SlotAssignment::create();
     m_slotAssignment->resolveAssignment(*this);
 }
 
+void ShadowRoot::distributeV1()
+{
+    if (!m_slotAssignment)
+        m_slotAssignment = SlotAssignment::create();
+    m_slotAssignment->resolveDistribution(*this);
+}
+
 DEFINE_TRACE(ShadowRoot)
 {
     visitor->trace(m_prev);