Upgrade custom elements when inserting a node

third_party/WebKit/Source/core/dom/custom/CustomElement.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/custom/CustomElement.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/QualifiedName.h"
 #include "core/dom/custom/CustomElementDefinition.h"
 #include "core/dom/custom/CustomElementsRegistry.h"
@@ skipping 168 matching lines @@
 void CustomElement::enqueueAttributeChangedCallback(Element* element,
     const QualifiedName& name,
     const AtomicString& oldValue, const AtomicString& newValue)
 {
     DCHECK_EQ(element->getCustomElementState(), CustomElementState::Custom);
     CustomElementDefinition* definition = definitionForElement(*element);
     if (definition->hasAttributeChangedCallback(name))
         definition->enqueueAttributeChangedCallback(element, name, oldValue, newValue);
 }
 
+void CustomElement::tryToUpgrade(Element* element)
+{
+    // Try to upgrade an element
+    // https://html.spec.whatwg.org/multipage/scripting.html#concept-try-upgrade
+
+    DCHECK_EQ(element->getCustomElementState(), CustomElementState::Undefined);
+
+    CustomElementsRegistry* registry = CustomElement::registry(*element);
+    if (!registry)
+        return;
+    if (CustomElementDefinition* definition = registry->definitionForName(element->localName()))
+        definition->enqueueUpgradeReaction(element);
+    else
+        registry->addCandidate(element);
+}
+
 } // namespace blink