Hide the CC button for <audio> with <track>s

LayoutTests/media/video-test.js

 
 var video = null;
 var mediaElement = document; // If not set, an event from any element will trigger a waitForEvent() callback.
 var console = null;
 var printFullTestDetails = true; // This is optionaly switched of by test whose tested values can differ. (see disableFullTestDetailsPrinting())
 var Failed = false;
 
 var track = null; // Current TextTrack being tested.
 var cues = null; // Current TextTrackCueList being tested.
 var numberOfTrackTests = 0;
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     }
     return console;
 }
 
 function findMediaElement()
 {
     try {
         video = document.getElementsByTagName('video')[0];
         if (video)
             mediaElement = video;
+        else {
+            audio = document.getElementsByTagName('audio')[0];
+            if (audio)
+                mediaElement = audio;
+        }
     } catch (ex) { }
 }
 
 function testAndEnd(testFuncString)
 {
     test(testFuncString, true);
 }
 
 function test(testFuncString, endit)
 {
@@ skipping 293 matching lines @@
 
         func();
     }
 
     requiredEvents = [];
     for (var i = 0; i < eventList.length; i++) {
         requiredEvents[i] = eventList[i][1];
         eventList[i][0].addEventListener(requiredEvents[i], _eventCallback, true);
     }
 }