deleted file mode 100644
--- a/dom/media/test/dynamic_redirect.sjs
+++ /dev/null
@@ -1,69 +0,0 @@
-function parseQuery(query, key) {
-  for (let p of query.split('&')) {
-    if (p == key) {
-      return true;
-    }
-    if (p.startsWith(key + "=")) {
-      return p.substring(key.length + 1);
-    }
-  }
-}
-
-// Return seek.ogv file content for the first request with a given key.
-// All subsequent requests return a redirect to a different-origin resource.
-function handleRequest(request, response)
-{
-  var query = request.queryString;
-  var key = parseQuery(query, "key");
-  var type = parseQuery(query, "type") || "application/octet-stream";
-  var resource = parseQuery(query, "res");
-  var nested = parseQuery(query, "nested") || false;
-
-  dump("Received request for key = "+ key +"\n");
-  if (!nested) {
-    if (getState(key) == "redirect") {
-      var origin = request.host == "mochi.test" ? "example.org" : "mochi.test:8888";
-      response.setStatusLine(request.httpVersion, 303, "See Other");
-      let url = "http://" + origin +
-                "/tests/dom/media/test/dynamic_redirect.sjs?nested&" + query;
-      dump("Redirecting to "+ url + "\n");
-      response.setHeader("Location", url);
-      response.setHeader("Content-Type", "text/html");
-      return;
-    }
-    setState(key, "redirect");
-  }
-  var file = Components.classes["@mozilla.org/file/directory_service;1"].
-                        getService(Components.interfaces.nsIProperties).
-                        get("CurWorkD", Components.interfaces.nsIFile);
-  var fis  = Components.classes['@mozilla.org/network/file-input-stream;1'].
-                        createInstance(Components.interfaces.nsIFileInputStream);
-  var bis  = Components.classes["@mozilla.org/binaryinputstream;1"].
-                        createInstance(Components.interfaces.nsIBinaryInputStream);
-  var paths = "tests/dom/media/test/" + resource;
-  var split = paths.split("/");
-  for (var i = 0; i < split.length; ++i) {
-    file.append(split[i]);
-  }
-  fis.init(file, -1, -1, false);
-
-  bis.setInputStream(fis);
-  var bytes = bis.readBytes(bis.available());
-  let [from, to] = request.getHeader("range").split("=")[1].split("-").map(s => parseInt(s));
-  to = to || Math.max(from, bytes.length - 1);
-  byterange = bytes.substring(from, to + 1);
-
-  let contentRange = "bytes "+ from +"-"+ to +"/"+ bytes.length;
-  let contentLength = (to - from + 1).toString();
-  dump("Response Content-Range = "+ contentRange +"\n");
-  dump("Response Content-Length = "+ contentLength +"\n");
-
-  response.setStatusLine(request.httpVersion, 206, "Partial Content");
-  response.setHeader("Content-Range", contentRange);
-  response.setHeader("Content-Length", contentLength, false);
-  response.setHeader("Content-Type", type, false);
-  response.setHeader("Accept-Ranges", "bytes", false);
-  response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
-  response.write(byterange, byterange.length);
-  bis.close();
-}

--- a/dom/media/test/mochitest.ini
+++ b/dom/media/test/mochitest.ini
@@ -429,17 +429,16 @@ support-files =
   detodos-short.webm
   detodos-short.webm^headers^
   detodos-recorder-test.opus
   detodos-recorder-test.opus^headers^
   detodos-short.opus
   detodos-short.opus^headers^
   dirac.ogg
   dirac.ogg^headers^
-  dynamic_redirect.sjs
   dynamic_resource.sjs
   eme.js
   file_access_controls.html
   file_autoplay_policy_unmute_pauses.html
   file_autoplay_policy_activation_window.html
   file_autoplay_policy_activation_frame.html
   flac-s24.flac
   flac-s24.flac^headers^

--- a/dom/media/test/test_mediarecorder_principals.html
+++ b/dom/media/test/test_mediarecorder_principals.html
@@ -41,18 +41,18 @@ function testPrincipals(resource) {
   if (!resource) {
     todo(false, "No types supported");
     return;
   }
   // First test: Load file from same-origin first, then get redirected to
   // another origin before attempting to record stream.
   let video = document.getElementById("v1");
   video.src =
-      "http://mochi.test:8888/tests/dom/media/test/dynamic_redirect.sjs?key=v1_" +
-      key + "&res=" + resource.name + "&type=" + resource.type;
+      "http://mochi.test:8888/tests/dom/media/test/midflight-redirect.sjs?key=v1_" +
+      key + "&resource=" + resource.name + "&type=" + resource.type;
   return new Promise(resolve => video.onloadedmetadata = resolve).then(() => {
     video.load();
     video.play();
     interval = setInterval(() => info("video.currentTime = "+ video.currentTime), 1000);
 
     let msg = "mediaRecorder.start() must throw SecurityError";
     return new Promise(resolve => video.onplaying = resolve)
     .then(() => waitUntil(() => video.currentTime > resource.duration / 5))
@@ -62,18 +62,18 @@ function testPrincipals(resource) {
       .then(() => ok(false, msg), e => is(e.name, "SecurityError", msg)), 0)
     .then(() => clearInterval(interval));
   })
   .then(() => {
     // Second test: Load file from same-origin first, but record ASAP, before
     // getting redirected to another origin.
     let video = document.getElementById("v2");
     video.src =
-        "http://mochi.test:8888/tests/dom/media/test/dynamic_redirect.sjs?key=v2_" +
-        key + "&res=" + resource.name + "&type=" + resource.type;
+        "http://mochi.test:8888/tests/dom/media/test/midflight-redirect.sjs?key=v2_" +
+        key + "&resource=" + resource.name + "&type=" + resource.type;
     let rec, hasStopped, hasEnded = new Promise(r => video.onended = r);
     let data = [];
 
     let msgNoThrow = "mediaRecorder.start() should not throw here";
     let msgSecErr = "mediaRecorder.onerror must fire SecurityError";
     let msgOnStop = "mediaRecorder.onstop must also have fired";
     return new Promise(resolve => video.onloadedmetadata = resolve).then(() => {
       rec = new MediaRecorder(video.mozCaptureStreamUntilEnded());

--- a/dom/media/test/test_mixed_principals.html
+++ b/dom/media/test/test_mixed_principals.html
@@ -42,18 +42,18 @@ https://bugzilla.mozilla.org/show_bug.cg
     function runTest(origin, shouldReadBackOnLoad) {
       return new Promise(function (resolve, reject) {
         // Load will redirect mid-flight, which will be detected and should error,
         // and we should no longer be able to readback.
         var noise = Math.floor(Math.random() * 100000000);
         var video = document.createElement("video");
         video.preload = "metadata";
         video.controls = true;
-        var url = "http://" + origin + "/tests/dom/media/test/dynamic_redirect.sjs?key="
-                  + noise + "&res=pixel_aspect_ratio.mp4"
+        var url = "http://" + origin + "/tests/dom/media/test/midflight-redirect.sjs?key="
+                  + noise + "&resource=pixel_aspect_ratio.mp4"
                   + "&type=video/mp4";
         SimpleTest.info("Loading from " + url);
         video.src = url;
         document.body.appendChild(video);
 
         once(video, "loadeddata", () => {
           is(canReadBack(video), shouldReadBackOnLoad, "Should be able to readback");
           video.play();