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

LayoutTests/media/media-element-play-after-eos.html

Index: LayoutTests/media/media-element-play-after-eos.html
diff --git a/LayoutTests/media/media-element-play-after-eos.html b/LayoutTests/media/media-element-play-after-eos.html
index 8d4ccde31f09a80490777cf10f0a95e4fa8dafab..67e608dfd76ee8f8c30df4b00d1f39d6d7b7582f 100644
--- a/LayoutTests/media/media-element-play-after-eos.html
+++ b/LayoutTests/media/media-element-play-after-eos.html
@@ -15,7 +15,7 @@
 
             function mediaLoadedMetadata()
             {
-                waitForEvent("playing", mediaPlaying);
+                waitForEventOnce("playing", mediaPlaying);
                 waitForEvent("pause", mediaPause);
                 waitForEvent("ended", mediaEnded);
                 run("mediaElement.play()");
@@ -34,11 +34,14 @@
             function mediaEnded()
             {
                 testExpected("mediaElement.ended", true);
- 
-                if (repeated)
+
+                if (repeated) {
                     endTest();
- 
+                    return;
+                }
+
                 repeated = true;
+                waitForEventOnce("playing", mediaPlaying);
                 run("mediaElement.play()");
             }
 
@@ -48,4 +51,3 @@
         <p>This tests ensure that media element emits the 'playing' event every time it starts playing after eos. It also ensure that 'pause' and 'ended' events are sent when media playback ends.</p>
     </body>
 </html>
-