Replace Element::isMediaElement() with isHTMLMediaElement

Source/core/html/shadow/MediaControlElementTypes.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 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.
@@ skipping 34 matching lines @@
 
 class Event;
 
 HTMLMediaElement* toParentMediaElement(Node* node)
 {
     if (!node)
         return 0;
     Node* mediaNode = node->shadowHost();
     if (!mediaNode)
         mediaNode = node;
-    if (!mediaNode || !mediaNode->isElementNode() || !toElement(mediaNode)->isMediaElement())
+    if (!isHTMLMediaElement(mediaNode))
         return 0;
 
     return toHTMLMediaElement(mediaNode);
 }
 
 MediaControlElementType mediaControlElementType(Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(node->isMediaControlElement());
     HTMLElement* element = toHTMLElement(node);
     if (element->hasTagName(inputTag))
@@ skipping 66 matching lines @@
     , m_currentValue(0)
 {
 }
 
 void MediaControlTimeDisplayElement::setCurrentValue(double time)
 {
     m_currentValue = time;
 }
 
 } // namespace WebCore