Implement Custom Elements inserted and removed callbacks.

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 8df5e79ab407fa858be4c1cfe83b049e1602ea14..b9b47ed1333105f2b1cd84ceb4c412c6ff0c0db0 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -939,9 +939,8 @@ void Element::attributeChanged(const QualifiedName& name, const AtomicString& ne
 
 inline void Element::attributeChangedFromParserOrByCloning(const QualifiedName& name, const AtomicString& newValue, AttributeModificationReason reason)
 {
-    if (RuntimeEnabledFeatures::customDOMElementsEnabled() && name == isAttr) {
-        document()->ensureCustomElementRegistry()->didGiveTypeExtension(this, newValue);
-    }
+    if (RuntimeEnabledFeatures::customDOMElementsEnabled() && name == isAttr)
+        document()->ensureCustomElementRegistry()->didGiveTypeExtension(this, newValue, true);
     attributeChanged(name, newValue, reason);
 }
 
@@ -1255,6 +1254,11 @@ Node::InsertionNotificationRequest Element::insertedInto(ContainerNode* insertio
     if (hasRareData())
         elementRareData()->clearClassListValueForQuirksMode();
 
+    if (isCustomElement()) {
+        if (CustomElementRegistry* registry = document()->registry())
+            registry->customElementWasInsertedIntoDocument(this);
+    }
+
     TreeScope* scope = insertionPoint->treeScope();
     if (scope != treeScope())
         return InsertionDone;
@@ -1311,8 +1315,15 @@ void Element::removedFrom(ContainerNode* insertionPoint)
     }
 
     ContainerNode::removedFrom(insertionPoint);
-    if (wasInDocument && hasPendingResources())
-        document()->accessSVGExtensions()->removeElementFromPendingResources(this);
+    if (wasInDocument) {
+        if (hasPendingResources())
+            document()->accessSVGExtensions()->removeElementFromPendingResources(this);
+
+        if (isCustomElement()) {
+            if (CustomElementRegistry* registry = document()->registry())
+                registry->customElementWasRemovedFromDocument(this);
+        }
+    }
 }
 
 void Element::createRendererIfNeeded(const AttachContext& context)