Replace Element::isMediaElement() with isHTMLMediaElement

Source/core/html/HTMLSourceElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2010 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
 
 PassRefPtr<HTMLSourceElement> HTMLSourceElement::create(Document& document)
 {
     return adoptRef(new HTMLSourceElement(document));
 }
 
 Node::InsertionNotificationRequest HTMLSourceElement::insertedInto(ContainerNode* insertionPoint)
 {
     HTMLElement::insertedInto(insertionPoint);
     Element* parent = parentElement();
-    if (parent && parent->isMediaElement())
-        toHTMLMediaElement(parentNode())->sourceWasAdded(this);
+    if (isHTMLMediaElement(parent))
+        toHTMLMediaElement(parent)->sourceWasAdded(this);
     return InsertionDone;
 }
 
 void HTMLSourceElement::removedFrom(ContainerNode* removalRoot)
 {
     Element* parent = parentElement();
     if (!parent && removalRoot->isElementNode())
         parent = toElement(removalRoot);
-    if (parent && parent->isMediaElement())
+    if (isHTMLMediaElement(parent))
         toHTMLMediaElement(parent)->sourceWasRemoved(this);
     HTMLElement::removedFrom(removalRoot);
 }
 
 void HTMLSourceElement::setSrc(const String& url)
 {
     setAttribute(srcAttr, AtomicString(url));
 }
 
 const AtomicString& HTMLSourceElement::media() const
@@ skipping 36 matching lines @@
     WTF_LOG(Media, "HTMLSourceElement::errorEventTimerFired - %p", this);
     dispatchEvent(Event::createCancelable(EventTypeNames::error));
 }
 
 bool HTMLSourceElement::isURLAttribute(const Attribute& attribute) const
 {
     return attribute.name() == srcAttr || HTMLElement::isURLAttribute(attribute);
 }
 
 }