diff --git a/embedding/components/windowwatcher/test/chrome.ini b/embedding/components/windowwatcher/test/chrome.ini
deleted file mode 100644
index 95601ade935c..000000000000
--- a/embedding/components/windowwatcher/test/chrome.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[DEFAULT]
-tags = openwindow
-
-[test_modal_windows.html]
-
diff --git a/embedding/components/windowwatcher/test/moz.build b/embedding/components/windowwatcher/test/moz.build
index ae0d7ccb8264..d1b0e2bda9b8 100644
--- a/embedding/components/windowwatcher/test/moz.build
+++ b/embedding/components/windowwatcher/test/moz.build
@@ -10,9 +10,4 @@ BROWSER_CHROME_MANIFESTS += [
 
 MOCHITEST_MANIFESTS += [
     'mochitest.ini',
-]
-
-MOCHITEST_CHROME_MANIFESTS += [
-    'chrome.ini',
-]
-
+]
\ No newline at end of file
diff --git a/embedding/components/windowwatcher/test/test_modal_windows.html b/embedding/components/windowwatcher/test/test_modal_windows.html
deleted file mode 100644
index 8a2c03be0e19..000000000000
--- a/embedding/components/windowwatcher/test/test_modal_windows.html
+++ /dev/null
@@ -1,56 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-Test that the parent can open modal windows, and that the modal window
-that is opened reports itself as being modal.
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test a modal window</title>
-
-  <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
-  <script src="chrome://mochikit/content/tests/SimpleTest/SpawnTask.js"></script>
-  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
-
-  <script type="application/javascript;version=1.8">
-  const {utils: Cu, interfaces: Ci} = Components;
-
-  Cu.import("resource://gre/modules/Services.jsm");
-  Cu.import("resource://testing-common/BrowserTestUtils.jsm");
-
-  add_task(function*() {
-    BrowserTestUtils.domWindowOpened().then((win) => {
-      let treeOwner = win.QueryInterface(Ci.nsIInterfaceRequestor)
-                         .getInterface(Ci.nsIWebNavigation)
-                         .QueryInterface(Ci.nsIDocShellTreeItem)
-                         .treeOwner
-      let chromeFlags = treeOwner.QueryInterface(Ci.nsIInterfaceRequestor)
-                                 .getInterface(Ci.nsIXULWindow)
-                                 .chromeFlags;
-      ok(chromeFlags & Ci.nsIWebBrowserChrome.CHROME_MODAL,
-         "Should have the modal chrome flag");
-
-      let wbc = treeOwner.QueryInterface(Ci.nsIInterfaceRequestor)
-                         .getInterface(Ci.nsIWebBrowserChrome);
-      ok(wbc.isWindowModal(), "Should report as modal");
-
-      win.close();
-    });
-
-    let modal = window.openDialog("data:text/html,<p>This is a modal window for test_modal_windows.html</p>",
-                                  "_blank", "modal", null);
-    // Since the modal runs a nested event loop, just to be on the safe side,
-    // we'll wait a tick of the main event loop before resolving the task.
-    yield new Promise(resolve => setTimeout(resolve, 0));
-  });
-
-  </script>
-</head>
-<body>
-<p id="display"></p>
-<div id="content" style="display: none">
-</div>
-<pre id="test">
-</pre>
-</body>
-</html>
\ No newline at end of file
