Let unresolved custom element go through CustomElementCallbackQueue.

Source/core/dom/custom/CustomElementCallbackInvocation.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CustomElementCallbackInvocation_h
 #define CustomElementCallbackInvocation_h
 
 #include "core/dom/custom/CustomElementLifecycleCallbacks.h"
+#include "core/dom/custom/CustomElementProcessingStep.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace WebCore {
 
-class Element;
-
-class CustomElementCallbackInvocation {
+class CustomElementCallbackInvocation : public CustomElementProcessingStep {

[dominicc (has gone to gerrit), 2013/12/14 02:42:39]

Could you add a FIXME to rename this class?

[Hajime Morrita, 2013/12/16 09:00:34]

OK, will do.

     WTF_MAKE_NONCOPYABLE(CustomElementCallbackInvocation);
 public:
     static PassOwnPtr<CustomElementCallbackInvocation> createInvocation(PassRefPtr<CustomElementLifecycleCallbacks>, CustomElementLifecycleCallbacks::CallbackType);
     static PassOwnPtr<CustomElementCallbackInvocation> createAttributeChangedInvocation(PassRefPtr<CustomElementLifecycleCallbacks>, const AtomicString& name, const AtomicString& oldValue, const AtomicString& newValue);
 
-    virtual ~CustomElementCallbackInvocation() { }
-    virtual void dispatch(Element*) = 0;
-    virtual bool isCreated() const { return false; }
-
 protected:
     CustomElementCallbackInvocation(PassRefPtr<CustomElementLifecycleCallbacks> callbacks)
         : m_callbacks(callbacks)
     {
     }
 
     CustomElementLifecycleCallbacks* callbacks() { return m_callbacks.get(); }
 
 private:
     RefPtr<CustomElementLifecycleCallbacks> m_callbacks;
 };
 
 }
 
 #endif // CustomElementCallbackInvocation_h