Let unresolved custom element go through CustomElementCallbackQueue.

Source/core/dom/custom/CustomElementRegistrationContext.cpp

Index: Source/core/dom/custom/CustomElementRegistrationContext.cpp
diff --git a/Source/core/dom/custom/CustomElementRegistrationContext.cpp b/Source/core/dom/custom/CustomElementRegistrationContext.cpp
index e248ab7cbf1b659f1b0a03dae0ca0b173c0e5057..b68f1533204b1aa25abf9b0091c4e9dd824ec782 100644
--- a/Source/core/dom/custom/CustomElementRegistrationContext.cpp
+++ b/Source/core/dom/custom/CustomElementRegistrationContext.cpp
@@ -74,16 +74,16 @@ PassRefPtr<Element> CustomElementRegistrationContext::createCustomTagElement(Doc
     }
 
     element->setCustomElementState(Element::WaitingForUpgrade);
-    resolve(element.get(), nullAtom);
+    resolveNewElement(element.get(), nullAtom);
     return element.release();
 }
 
 void CustomElementRegistrationContext::didGiveTypeExtension(Element* element, const AtomicString& type)
 {
-    resolve(element, type);
+    resolveNewElement(element, type);
 }
 
-void CustomElementRegistrationContext::resolve(Element* element, const AtomicString& typeExtension)
+void CustomElementRegistrationContext::resolveNewElement(Element* element, const AtomicString& typeExtension)
 {
     // If an element has a custom tag name it takes precedence over
     // the "is" attribute (if any).
@@ -100,6 +100,15 @@ void CustomElementRegistrationContext::resolve(Element* element, const AtomicStr
         didCreateUnresolvedElement(descriptor, element);
 }
 
+void CustomElementRegistrationContext::resolvePoppedElement(Element* element, const CustomElementDescriptor& descriptor)
+{
+    CustomElementDefinition* definition = m_registry.find(descriptor);
+    if (definition)
+        didResolveElement(definition, element);
+    else
+        didFailResolution(descriptor, element);
+}
+
 void CustomElementRegistrationContext::didResolveElement(CustomElementDefinition* definition, Element* element)
 {
     CustomElement::define(element, definition);
@@ -108,6 +117,12 @@ void CustomElementRegistrationContext::didResolveElement(CustomElementDefinition
 void CustomElementRegistrationContext::didCreateUnresolvedElement(const CustomElementDescriptor& descriptor, Element* element)
 {
     ASSERT(element->customElementState() == Element::WaitingForUpgrade);
+    CustomElementCallbackScheduler::scheduleResolutionCallback(descriptor, element);
+}
+
+void CustomElementRegistrationContext::didFailResolution(const CustomElementDescriptor& descriptor, Element* element)
+{
+    ASSERT(element->customElementState() == Element::WaitingForUpgrade);
     m_candidates.add(descriptor, element);
 }