Let unresolved custom element go through CustomElementCallbackQueue.

Source/core/dom/custom/CustomElementCallbackScheduler.h

Index: Source/core/dom/custom/CustomElementCallbackScheduler.h
diff --git a/Source/core/dom/custom/CustomElementCallbackScheduler.h b/Source/core/dom/custom/CustomElementCallbackScheduler.h
index 0311d05662332ee6d59398ba6557952b2ebc8cc2..7eb0ab0f79a8ffddaeb16361bf4fc9e68f64fda9 100644
--- a/Source/core/dom/custom/CustomElementCallbackScheduler.h
+++ b/Source/core/dom/custom/CustomElementCallbackScheduler.h
@@ -39,6 +39,7 @@
 
 namespace WebCore {
 
+class CustomElementDescriptor;
 class CustomElementLifecycleCallbacks;
 class Element;
 
@@ -48,6 +49,7 @@ public:
     static void scheduleCreatedCallback(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
     static void scheduleEnteredViewCallback(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
     static void scheduleLeftViewCallback(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
+    static void scheduleResolutionCallback(const CustomElementDescriptor&, PassRefPtr<Element>);

[dominicc (has gone to gerrit), 2013/12/13 05:11:16]

Likewise we can call this scheduleResolveStep, and in a follow up changelist
scheduleCreatedCallback -> scheduleUpgradeStep.

I think schedule{EnteredView,LeftView,AttributeChanged}Callback names are OK.

[Hajime Morrita, 2013/12/13 07:02:29]

Done. Renaming scheduleCreatedCallback() will come with follow-up renaming
patch.

 
 protected:
     friend class CustomElementCallbackDispatcher;