Bug 1383122 - P4. Don't set src attribute to empty string. r=jwwang

MozReview-Commit-ID: EzQCVIIjOIe

--HG--
extra : rebase_source : af21c6749f22ae98cf3d81577eb0476dcca99035

dom/media/test/manifest.js

@@ -1558,13 +1558,10 @@ function getMajorMimeType(mimetype) {
 // Force releasing decoder to avoid timeout in waiting for decoding resource.
 function removeNodeAndSource(n) {
   n.remove();
-  // Clearing srcObject and/or src will actually set them to some default
-  // URI that will fail to load, so make sure we don't produce a spurious
-  // bailing error.
-  n.onerror = null;
   // reset |srcObject| first since it takes precedence over |src|.
   n.srcObject = null;
-  n.src = "";
+  n.removeAttribute("src");
+  n.load();
   while (n.firstChild) {
     n.firstChild.remove();
   }