diff -r 000000000000 -r 6474c204b198 image/test/browser/head.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/image/test/browser/head.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+const RELATIVE_DIR = "image/test/browser/";
+const TESTROOT = "http://example.com/browser/" + RELATIVE_DIR;
+const TESTROOT2 = "http://example.org/browser/" + RELATIVE_DIR;
+
+var chrome_root = getRootDirectory(gTestPath);
+const CHROMEROOT = chrome_root;
+
+function getImageLoading(doc, id) {
+  var htmlImg = doc.getElementById(id);
+  return htmlImg.QueryInterface(Ci.nsIImageLoadingContent);
+}
+
+// Tries to get the Moz debug image, imgIContainerDebug. Only works
+// in a debug build. If we succeed, we call func().
+function actOnMozImage(doc, id, func) {
+  var imgContainer = getImageLoading(doc, id).getRequest(Ci.nsIImageLoadingContent.CURRENT_REQUEST).image;
+  var mozImage;
+  try {
+    mozImage = imgContainer.QueryInterface(Ci.imgIContainerDebug);
+  }
+  catch (e) {
+    return false;
+  }
+  func(mozImage);
+  return true;
+}