Introduce isHTMLVideoElement and toHTMLVideoElement

Source/core/html/MediaDocument.cpp

 /*
  * Copyright (C) 2008 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 72 matching lines @@
     RefPtr<Element> meta = document()->createElement(metaTag, false);
     meta->setAttribute(nameAttr, "viewport");
     meta->setAttribute(contentAttr, "width=device-width");
     head->appendChild(meta, IGNORE_EXCEPTION);
 
     RefPtr<Element> body = document()->createElement(bodyTag, false);
     rootElement->appendChild(body, IGNORE_EXCEPTION);
 
     RefPtr<Element> mediaElement = document()->createElement(videoTag, false);
 
-    m_mediaElement = static_cast<HTMLVideoElement*>(mediaElement.get());
+    m_mediaElement = toHTMLVideoElement(mediaElement.get());
     m_mediaElement->setAttribute(controlsAttr, "");
     m_mediaElement->setAttribute(autoplayAttr, "");
 
     m_mediaElement->setAttribute(nameAttr, "media");
 
     RefPtr<Element> sourceElement = document()->createElement(sourceTag, false);
     HTMLSourceElement* source = static_cast<HTMLSourceElement*>(sourceElement.get());
     source->setSrc(document()->url());
 
     if (DocumentLoader* loader = document()->loader())
@@ skipping 22 matching lines @@
 
 PassRefPtr<DocumentParser> MediaDocument::createParser()
 {
     return MediaDocumentParser::create(this);
 }
 
 static inline HTMLVideoElement* descendentVideoElement(Node* node)
 {
     ASSERT(node);
 
-    if (node->hasTagName(videoTag))
-        return static_cast<HTMLVideoElement*>(node);
+    if (isHTMLVideoElement(node))
+        return toHTMLVideoElement(node);
 
     RefPtr<NodeList> nodeList = node->getElementsByTagNameNS(videoTag.namespaceURI(), videoTag.localName());
-   
+
     if (nodeList.get()->length() > 0)
-        return static_cast<HTMLVideoElement*>(nodeList.get()->item(0));
+        return toHTMLVideoElement(nodeList.get()->item(0));
 
     return 0;
 }
 
 void MediaDocument::defaultEventHandler(Event* event)
 {
     // Match the default Quicktime plugin behavior to allow 
     // clicking and double-clicking to pause and play the media.
     Node* targetNode = event->target()->toNode();
     if (!targetNode)
@@ skipping 11 matching lines @@
                 if (video->canPlay())
                     video->play();
             } else
                 video->pause();
             event->setDefaultHandled();
         }
     }
 }
 
 }