Media element resource selection algorithm should "await a stable state"

third_party/WebKit/LayoutTests/media/video-delay-load-event.html

Index: third_party/WebKit/LayoutTests/media/video-delay-load-event.html
diff --git a/third_party/WebKit/LayoutTests/media/video-delay-load-event.html b/third_party/WebKit/LayoutTests/media/video-delay-load-event.html
index 35922274cc01f830a919faa84e7d620845bfc49d..a65fc15e136e0872f554a1e8fa2c7815e945c4cc 100644
--- a/third_party/WebKit/LayoutTests/media/video-delay-load-event.html
+++ b/third_party/WebKit/LayoutTests/media/video-delay-load-event.html
@@ -5,7 +5,7 @@
 <script src="media-file.js"></script>
 <video id="video1"></video>
 <video id="video2"></video>
-<video id="video3"><source></source></video>
+<video id="video3"></video>
 <script>
 async_test(function(t) {
     assertVideoNoSrcNoLoad(document.getElementById("video1"));
@@ -14,9 +14,11 @@ async_test(function(t) {
     video.src = findMediaFile("video", "content/test");
     assertVideoSrcNoLoad(video);
 
-    var source = document.querySelector("source");
+    var source = document.createElement("source");
     source.src = findMediaFile("video", "content/test");
-    assertVideoSrcNoLoad(document.getElementById("video3"));
+    var video3 = document.getElementById("video3");
+    video3.appendChild(source);
+    assertVideoSrcNoLoad(video3);
 
     window.onload = t.step_func_done(function() {
         assertVideoNoSrcNoLoad(document.getElementById("video1"));