Use Traversal<HTMLSourceElement> to find the next source candidate

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 481 matching lines @@
 
     // The last time a timeupdate event was sent (wall clock).
     double m_lastTimeUpdateEventWallTime;
 
     // The last time a timeupdate event was sent in movie time.
     double m_lastTimeUpdateEventMovieTime;
 
     // Loading state.
     enum LoadState { WaitingForSource, LoadingFromSrcAttr, LoadingFromSourceElement };
     LoadState m_loadState;
-    RefPtrWillBeMember<HTMLSourceElement> m_currentSourceNode;
-    RefPtrWillBeMember<Node> m_nextChildNodeToConsider;
+    RefPtrWillBeMember<HTMLSourceElement> m_currentSourceElement;
+    RefPtrWillBeMember<HTMLSourceElement> m_nextSourceElement;
 
     // "Deferred loading" state (for preload=none).
     enum DeferredLoadState {
         // The load is not deferred.
         NotDeferred,
         // The load is deferred, and waiting for the task to set the
         // delaying-the-load-event flag (to false).
         WaitingForStopDelayingLoadEventTask,
         // The load is the deferred, and waiting for a triggering event.
         WaitingForTrigger,
@@ skipping 108 matching lines @@
 inline bool isHTMLMediaElement(const HTMLElement& element)
 {
     return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } //namespace
 
 #endif