Support slotchange event

third_party/WebKit/Source/core/dom/Element.h

Index: third_party/WebKit/Source/core/dom/Element.h
diff --git a/third_party/WebKit/Source/core/dom/Element.h b/third_party/WebKit/Source/core/dom/Element.h
index dfa90ecdc8a1433b03f46907ea335c925d9d4b49..37659f235de42bad1aba10255a2ff83b162416ee 100644
--- a/third_party/WebKit/Source/core/dom/Element.h
+++ b/third_party/WebKit/Source/core/dom/Element.h
@@ -871,6 +871,10 @@ inline Node::InsertionNotificationRequest Node::insertedInto(ContainerNode* inse
         setFlag(IsInShadowTreeFlag);
     if (childNeedsDistributionRecalc() && !insertionPoint->childNeedsDistributionRecalc())
         insertionPoint->markAncestorsWithChildNeedsDistributionRecalc();
+    if (document().shadowCascadeOrder() == ShadowCascadeOrder::ShadowCascadeV1) {

[hayato, 2016/04/18 07:16:31]

Given that CSS is no longer only the client of this flag, 
it would be better to rename shadowCascadeOrder to more general name.

[yuzuchan, 2016/04/18 09:43:27]

Found out that I do not need to use the function here. Will rename it in another
CL.

+        if (isChildOfV1ShadowHost() || isChildOfSlot())
+            document().updateAssignment();
+    }
     return InsertionDone;
 }