Fix LayoutTests that assume canplay, playing, and canplaythrough will only fire once.

LayoutTests/media/video-played.js

 
 var expectedStartTimes = new Array();
 var expectedEndTimes = new Array();
 var timeRangeCount = 0;
 var currentTimeRange = 0;
 var currentTest = 0;
 var willPauseInExistingRange = false;
 var willExtendAnExistingRange = false;
 
 var testStartTime = 0;
@@ skipping 98 matching lines @@
     }
 
     run("video.play()");
 
     var startTime = nowInSecs();
     var playedFromTime = video.currentTime;
     var playDuration = milliToSecs(milliseconds);
     var callPauseIfTimeIsReached = function ()
     {
         var playedTime = video.currentTime - playedFromTime;
-        
+
         if (playedTime < 0) {
             // Deal with 'loop' attribue. This work only once, hence the warning
             // At the begining of playForMillisecs()
             playedTime = video.duration - playedFromTime + video.currentTime;
         }
 
         var elapsed = nowInSecs() - startTime;
         if (elapsed > 2) {
             // Just in case something goes wrong.
             failTest("ERROR: test stalled, waited " + elapsed + " seconds for movie to play " + playedTime + " seconds");
@@ skipping 16 matching lines @@
 function videoPlayedMain()
 {
     findMediaElement();
     
     video.src = findMediaFile("video", "content/test");
     
     waitForEvent("error");
     waitForEvent("loadstart");
     waitForEvent("ratechange");
     waitForEvent("loadedmetadata");
-    waitForEvent("canplay", canplay); // Will trigger nextTest() which launches the tests.
+    waitForEventOnce("canplay", canplay); // Will trigger nextTest() which launches the tests.
     waitForEvent("pause", pause);
     
     video.load();
 }