Clear the custom element's reaction queue if upgrade fails.

third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.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/CustomElementDefinition.h"
 
 #include "core/dom/Attr.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementAdoptedCallbackReaction.h"
 #include "core/dom/custom/CustomElementAttributeChangedCallbackReaction.h"
 #include "core/dom/custom/CustomElementConnectedCallbackReaction.h"
 #include "core/dom/custom/CustomElementDisconnectedCallbackReaction.h"
 #include "core/dom/custom/CustomElementReaction.h"
+#include "core/dom/custom/CustomElementReactionStack.h"
 #include "core/dom/custom/CustomElementUpgradeReaction.h"
 #include "core/html/HTMLElement.h"
 
 namespace blink {
 
 CustomElementDefinition::CustomElementDefinition(
     const CustomElementDescriptor& descriptor)
     : m_descriptor(descriptor) {}
 
 CustomElementDefinition::CustomElementDefinition(
@@ skipping 122 matching lines @@
   if (element->isConnected() && hasConnectedCallback())
     enqueueConnectedCallback(element);
 
   bool succeeded = false;
   {
     ConstructionStackScope constructionStackScope(this, element);
     succeeded = runConstructor(element);
   }
   if (!succeeded) {
     element->setCustomElementState(CustomElementState::Failed);
+    CustomElementReactionStack::current().clearQueue(element);
     return;
   }
 
   element->setCustomElementDefinition(this);
 }
 
 bool CustomElementDefinition::hasAttributeChangedCallback(
     const QualifiedName& name) const {
   return m_observedAttributes.contains(name.localName());
 }
@@ skipping 43 matching lines @@
     element->synchronizeAttribute(name);
   for (const auto& attribute : element->attributesWithoutUpdate()) {
     if (hasAttributeChangedCallback(attribute.name())) {
       enqueueAttributeChangedCallback(element, attribute.name(), nullAtom,
                                       attribute.value());
     }
   }
 }
 
 }  // namespace blink