Add UseCounter for HTMLSourceElement.media

Source/core/html/HTMLMediaElement.cpp

 /*
  * 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 2863 matching lines @@
         node = potentialSourceNodes[i].get();
         if (lookingForStartNode && m_nextChildNodeToConsider != node)
             continue;
         lookingForStartNode = false;
 
         if (!node->hasTagName(sourceTag))
             continue;
         if (node->parentNode() != this)
             continue;
 
+        UseCounter::count(document(), UseCounter::SourceElementCandidate);
         source = toHTMLSourceElement(node);
 
         // If candidate does not have a src attribute, or if its src attribute's value is the empty string ... jump down to the failed step below
         mediaURL = source->getNonEmptyURLAttribute(srcAttr);
 #if !LOG_DISABLED
         if (shouldLog)
             LOG(Media, "HTMLMediaElement::selectNextSourceChild - 'src' is %s", urlForLoggingMedia(mediaURL).utf8().data());
 #endif
         if (mediaURL.isEmpty())
             goto check_again;
 
         if (source->fastHasAttribute(mediaAttr)) {
             MediaQueryEvaluator screenEval("screen", document().frame(), renderer() ? renderer()->style() : 0);
             RefPtr<MediaQuerySet> media = MediaQuerySet::create(source->media());
 #if !LOG_DISABLED
             if (shouldLog)
                 LOG(Media, "HTMLMediaElement::selectNextSourceChild - 'media' is %s", source->media().utf8().data());
 #endif
-            if (!screenEval.eval(media.get()))
+            if (!screenEval.eval(media.get())) {
+                UseCounter::count(document(), UseCounter::SourceElementNonMatchingMedia);
                 goto check_again;
+            }
         }
 
         type = source->type();
         // FIXME(82965): Add support for keySystem in <source> and set system from source.
         if (type.isEmpty() && mediaURL.protocolIsData())
             type = mimeTypeFromDataURL(mediaURL);
         if (!type.isEmpty() || !system.isEmpty()) {
 #if !LOG_DISABLED
             if (shouldLog)
                 LOG(Media, "HTMLMediaElement::selectNextSourceChild - 'type' is '%s' - key system is '%s'", type.utf8().data(), system.utf8().data());
@@ skipping 972 matching lines @@
 {
     scheduleLayerUpdate();
 }
 
 bool HTMLMediaElement::isInteractiveContent() const
 {
     return fastHasAttribute(controlsAttr);
 }
 
 }