Implement Custom Elements' attributeChangedCallback.

Source/core/dom/CustomElementCallbackDispatcher.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 48 matching lines @@
         {
             if (s_elementQueueStart != s_elementQueueEnd)
                 processElementQueueAndPop();
             s_elementQueueStart = m_savedElementQueueStart;
         }
 
     private:
         size_t m_savedElementQueueStart;
     };
 
+    void enqueueAttributeChangedCallback(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>, const AtomicString& name, const AtomicString& oldValue, const AtomicString& newValue);
     void enqueueCreatedCallback(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
 
     // Returns true if more work may have to be performed at the
     // checkpoint by this or other workers (for example, this work
     // invoked author scripts)
     bool dispatch();
 
 private:
     CustomElementCallbackDispatcher()
     {
@@ skipping 16 matching lines @@
     static size_t s_elementQueueEnd;
 
     static bool inCallbackDeliveryScope() { return s_elementQueueStart; }
 
     typedef int ElementQueue;
     static ElementQueue currentElementQueue() { return ElementQueue(s_elementQueueStart); }
 
     static void processElementQueueAndPop();
     void processElementQueueAndPop(size_t start, size_t end);
 
+    CustomElementCallbackQueue* createCallbackQueue(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
+    CustomElementCallbackQueue* ensureCallbackQueue(PassRefPtr<CustomElementLifecycleCallbacks>, PassRefPtr<Element>);
+
     // The processing stack, flattened. Element queues lower in the
     // stack appear toward the head of the vector. The first element
     // is a null sentinel value.
     Vector<CustomElementCallbackQueue*> m_flattenedProcessingStack;
 
     typedef HashMap<Element*, OwnPtr<CustomElementCallbackQueue> > ElementCallbackQueueMap;
     ElementCallbackQueueMap m_elementCallbackQueueMap;
 };
 
 }
 
 #endif // CustomElementCallbackDispatcher_h