Replace HTMLMediaElement::isVideo() with isHTMLVideoElement

Source/core/html/HTMLMediaElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 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 66 matching lines @@
     static blink::WebMimeRegistry::SupportsType supportsType(const ContentType&, const String& keySystem = String());
 
     static void setMediaStreamRegistry(URLRegistry*);
     static bool isMediaStreamURL(const String& url);
 
     // Do not use player().
     // FIXME: Replace all uses with webMediaPlayer() and remove this API.
     MediaPlayer* player() const { return m_player.get(); }
     blink::WebMediaPlayer* webMediaPlayer() const { return m_player ? m_player->webMediaPlayer() : 0; }
 
-    virtual bool isVideo() const = 0;
     virtual bool hasVideo() const OVERRIDE { return false; }
     virtual bool hasAudio() const OVERRIDE FINAL;
 
     bool supportsSave() const;
 
     blink::WebLayer* platformLayer() const;
 
     enum DelayedActionType {
         LoadMediaResource = 1 << 0,
         LoadTextTrackResource = 1 << 1,
@@ skipping 451 matching lines @@
 inline bool isHTMLMediaElement(const Node* node)
 {
     return node && isHTMLMediaElement(*node);
 }
 
 DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } //namespace
 
 #endif