Rewrite Shadow DOM distribution engine to support partial synchronous distribution for v1

third_party/WebKit/Source/core/dom/ContainerNode.cpp

Index: third_party/WebKit/Source/core/dom/ContainerNode.cpp
diff --git a/third_party/WebKit/Source/core/dom/ContainerNode.cpp b/third_party/WebKit/Source/core/dom/ContainerNode.cpp
index d509f3b3c8fbdbe9d5186bd4c8bbadfe911aed59..a57cc701b61a798ffe0e0e6583e7f8a9fae3f3dd 100644
--- a/third_party/WebKit/Source/core/dom/ContainerNode.cpp
+++ b/third_party/WebKit/Source/core/dom/ContainerNode.cpp
@@ -692,6 +692,9 @@ void ContainerNode::notifyNodeInserted(Node& root, ChildrenChangeSource source)
 #endif
     DCHECK(!root.isShadowRoot());
 
+    if (document().containsV1ShadowTree())
+        root.checkSlotChangeAfterInserted();
+
     InspectorInstrumentation::didInsertDOMNode(&root);
 
     NodeVector postInsertionNotificationTargets;