Replace flaky test, wrangle with harness/infra

third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js

Index: third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js
diff --git a/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js b/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js
index 092af85c5cdb430c6de0757be268e1bf4e8cfdbf..2dab53c2a6f643f348cf8bf5fb079adcf4a80462 100644
--- a/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js
+++ b/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-util.js
@@ -407,11 +407,17 @@
     {
         return media_test(function(test)
         {
-            var mediaTag = document.createElement("video");
+            var tagType = properties.audio_only ? "audio" : "video";
+            var mediaTag = document.createElement(tagType);
             document.body.appendChild(mediaTag);
 
             // Overload done() so that element added to the document can be removed.
             test.removeMediaElement_ = true;
+            if (typeof(properties.remove_element_when_done) != undefined) {
+                // Some tests may want the mediaElement to stick around.
+                test.removeMediaElement_ = properties.remove_element_when_done
+            }
+
             var oldTestDone = test.done.bind(test);
             test.done = function()
             {