Add "Failed" custom element state

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/CEReactionsScope.h"
 #include "core/dom/custom/CustomElementDefinition.h"
 #include "core/dom/custom/CustomElementReactionStack.h"
 #include "core/dom/custom/CustomElementsRegistry.h"
 #include "core/dom/custom/V0CustomElement.h"
 #include "core/dom/custom/V0CustomElementRegistrationContext.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/html/HTMLElement.h"
+#include "core/html/HTMLUnknownElement.h"
 #include "platform/text/Character.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace blink {
 
 CustomElementsRegistry* CustomElement::registry(const Element& element)
 {
     return registry(element.document());
 }
 
@@ skipping 133 matching lines @@
         element = toHTMLElement(v0element);
     } else {
         element = HTMLElement::create(tagName, document);
     }
 
     element->setCustomElementState(CustomElementState::Undefined);
 
     return element;
 }
 
+HTMLElement* CustomElement::createFailedElement(Document& document, const QualifiedName& tagName)
+{
+    DCHECK(shouldCreateCustomElement(document, tagName));
+
+    // "create an element for a token":
+    // https://html.spec.whatwg.org/multipage/syntax.html#create-an-element-for-the-token
+
+    // 7. If this step throws an exception, let element be instead a new element
+    // that implements HTMLUnknownElement, with no attributes, namespace set to
+    // given namespace, namespace prefix set to null, custom element state set
+    // to "failed", and node document set to document.
+
+    HTMLElement* element = HTMLUnknownElement::create(tagName, document);
+    element->setCustomElementState(CustomElementState::Failed);
+    return element;
+}
+
 void CustomElement::enqueue(Element* element, CustomElementReaction* reaction)
 {
     // To enqueue an element on the appropriate element queue
     // https://html.spec.whatwg.org/multipage/scripting.html#enqueue-an-element-on-the-appropriate-element-queue
 
     // If the custom element reactions stack is not empty, then
     // Add element to the current element queue.
     if (CEReactionsScope* current = CEReactionsScope::current()) {
         current->enqueueToCurrentQueue(element, reaction);
         return;
@@ skipping 39 matching lines @@
     CustomElementsRegistry* registry = CustomElement::registry(*element);
     if (!registry)
         return;
     if (CustomElementDefinition* definition = registry->definitionForName(element->localName()))
         definition->enqueueUpgradeReaction(element);
     else
         registry->addCandidate(element);
 }
 
 } // namespace blink